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VELVET MITES FROM NORTHERN MICHIGAN DECIDUOUS FOREST

By
Hong-ren Yao

A DISSERTATION

Submitted to
Michigan State University
in partial fulfillment of the requirements
for the degree of

DOCTOR OF PHILOSOPHY

Department o f Zoology

1994

UMI Number: 9525027

UMI MicroEorm 9525027
Copyright 1995, by UMI Company. All rights reserved.
This microform edition is protected against unauthorized
copying under Title 17, United States Code.

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ABSTRACT
VELVET MITES FROM NORTHERN MICHIGAN DECIDUOUS FOREST
By
Hong-ren Yao

Among 25 species of velvet mites collected in Michigan’s Upper Peninsula, 13
species and one genus were found to be new to science. Six species were described based
on all developmental stages, including laboratory reared specimens. Three species were
described in both larval and adult stages. Description of three more species was based
on larvae only. One species was described in the adult form. Larval and adult forms of
several species (Abrolophus welbourni n. sp., Trombidium auroraense, Eutrombidium
locustarum, Leptus solitarius n. sp., L. sylvestratilis n. sp., Erythraeus michiganensis n.
sp., and Podothrombium Juciirn n. sp.) were correlated by laboratory and field
observations. Based on laboratory rearing and field collections, larvae of a species
previously placed in Hauptmannia were shown to belong in the genus Abrolophus.
The life histories of 11 species were documented in field and laboratory studies.
Three life cycle types were distinguishable according to overwintering life stages: 1)
diapausing tritonymphs; 2) eggs; and 3) diapausing protonymphs.
A list of arthropod hosts accepted by 18 species of mites was compiled from field
observations and laboratory tests. Mechanisms of coexistence for larvae of Trombidium
auroraense, Leptus sylvestratilis and Eutrombidium locustarum sharing a single host
resource (Melanoplus differentialis ) were documented.
Diel activity patterns of the larvae of two dominant mite species were observed

in the field by means of pit-trapping. These patterns were found to be partly related to
relative humidity, an observation confirmed by the laboratory response of species to
different relative humidities. The duration of developmental stages of three dominant
species (T. auroraense, E. locustarum and L. sylvestratilis)

was documented under

laboratory conditions. A life table was drawn up for the above three species based on 3
years o f laboratory rearing.

In memory of unforgettable years in East Lansing, Michigan State University,
in memory of the good American people in my life.......

ACKNOWLEDGMENTS

Special thanks are given to my all committee members, Drs. R. J. Snider, R. M.
Snider, F. Stehr and J. Atkinson, especially my major professor Dr. R. J. Snider.
Without their encouragement and advice through the years, I would not have been able
to finish the degree in the States since the roads here are very slippery for a Chinese.
I am also thankful to Dr. Calvin Welboum, Ohio State University, for checking my
species determinations and classification; and to Mr. Mark Thogerson for his help on
computer work.

v

PR E FA C E
Mention o f "Project ELF" will be made at several points in this dissertation in
reference to a long-term ecological monitoring project in M ichigan’s Upper Peninsula,
(funded by the U. S. Navy*) and led by Richard J. Snider and Renate M. Snider. While
I was actively participating in this project’s research, I was also able to gather much of
the data presented below. Most of my results were derived from personal collections and
experiments, but Project ELF supplied additional specimens and information which
augmented my own database. Project ELF information pertaining to velvet mites was
obtained mainly by pit-trapping at weekly intervals from May through October (ref.
Snider and Snider, 1987 for details); additional specimens stemmed from heat-extraction
of soil and litter samples.

*) Partial support for this research was provided by the Space and Naval Warfare
Systems Command through a subcontract to IIT Research Institute under contracts
N 00039-88-C-0065 and N0039-93-C-0001.

TABLE OF CONTENTS

LIST OF TABLES

x

LIST OF FIGURES

xii

INTRODUCTION

1

PART I. CLASSIFICATION

5

1. MATERIALS ANDMETHODS

6

2. SITE DESCRIPTION

8

3. RESULTS

15

3. 1. Systematic list of velvet mite species collected in Michigan’s Upper
Peninsula

15

3. 2. Description of new species:
Leptus sylvestratilis

n. sp.

18

Leptus solitarius

n. sp.

29

Erythraeus michiganensis

n. sp.

47

Erythraeus septemsetalis

n. sp.

65

n. sp.

68

n. sp.

79

n. sp.

82

Abrolophus welboumi
Abrolophus channingensis
Charletonia curalia
vii

Balaustium nonasum

n. sp.

A new p’ nus and a new species

92
102

Allothrombium carum

n. sp.

112

Podothrombium Jucum

n. sp.

119

Calyptostoma nivalis

n. sp.

131

Hexathrombium bicomarum

n. sp.

142

PART II. ECOBIOLOGICAL STUDIES

149

1. MATERIALS AND METHODS

150

1 . 1 . Rearing mites from adults

150

1 . 2 . Rearing mites from hosts

151

1. 3. Field observations of diel activity

151

1. 4. Host preference studies

152

1. 5. Response of three species to relative humidity

153

2. RESULTS

153

2. 1. Life history o f 11 species

153

2. 2. Host and prey selection

159

2. 3. Responses of three common species to relative humidity

170

2. 4. Diel activity patterns of two common species

173

2. 5. Oviposition and fecundity of four species

176

viii

2. 6. Developmental rates of three species under laboratory conditions

177

2. 7. Behavior

181

3. DISCUSSION

183

SUMMARY

187

REFERENCES

191

ix

LIST OF TABLES

Table

Page

1. Texture and thickness of the upper soil profile at the study site: means ± SE
(N = 20).
9
2. Macronutrients (Kg/ha), pH and percent Organic Matter of the soil in the study
site.
10
3. Densities and importance values {relative density + relative dominance + relative
frequency) of tree and understory species in the study site.
11
4. Seasonal occurrence of insect hosts for velvet mites collected in the field (based ob
1990-1992 data).
13
5. Morphological features of five groups of Leptus larvae (adapted from Beron,
1975; Fain etal, 1987).
39
6. Morphological differences between two UP Leptus and five other Leptus in
America.
40
7. Major differences between L. ignotus and L. solitarius: leg length, number of
solenidia and dorsal setae and measurements of sclerite.
42
8. Main charater differences between three American Charletonia species:
measurements of length of sclerite and leg segments; ratio of the length of leg
segments and of sclerite.
91
9. Distinguishing charaters of Allothrombium carium n. sp. and three other close
species (larvae).
118
10. Types of life histories of 11 velvet mite species: seasonal appearance of life stages.
LV = larvae, PN — Protonymph, DN = Deutonymph, TN =Tritonymph, Ad =
Adult.
155
x

11. Type I life history: breakdown into seasonal events. Abbreviations as in Table 10.
155
12. Type II life history: breakdown into seasonal events. GF = Gravid females, other
abbreviations as in Table 10.
156
13. Type III life history: breakdown into seasonal events. Abbreviations as in Table 10.
156
14. Seasonal appearance of two species (A. welbourni and T. auroraense) in two years.
158
15. Summary data of host records of L. solitaries larvae in 1990 and 1991; data are
given as number o f hosts carrying larvae/total number of hosts examined. 160
16. Host usage by T. auroraense in July and August, 1990: data are given as number
o f hosts carrying larvae/total number of hosts examined.
161
17. Host and prey preferences of seven species of velvet mites: data are given in
numbers o f hosts with larvae attached/total number of hosts collected; (N) =
nymphs o f hosts.
162
18. Host acceptance by six mite species under laboratory conditions: data are given
in number of hosts with mites attached (of 150 host individuals introduced),
number o f species in parentheses.
165
19. A list o f host records for velvet mites in a michigan deciduous forest.

166

20. Survival o f deutonymphs and size (/<m) of emerging adults of Trombidium
auroraense overwintered in the laboratory (4 ± 1.5 °C, RH = 90%, light =
0)
167
21. Attachment sites o f larval L. sylvestratilis on grasshoppers: values represent the
number o f larvae found on a given anatomical area of the host.
169

22. Duration o f oviposition period and number of eggs laid per female of four species.
176
23. Duration in days o f the developmental stages of three species under laboratory
conditions.
179
24. Life table of three mites in laboratory rearing.
xi

180

LIST OF FIGURES

Fig

Page

1-11. Leptus sylvestratilis n. sp. (larva, deutonymph and adult female).

27

5a-c. Leptus sylvestratilis n. sp. (larva).

34

12-14. Leptus solitarius (larva).

34

15-19. Leptus solitarius n. sp. (larva, deutonymph and adult female).

36

20-24. Erythraeus michiganensis n. sp. (Larva and deutonymph).

54

22a-d. Erythraeus michiganensis n. sp. (larva).

56

25-26. Erythraeus michiganensis n. sp. (deutonymph and adult female).

56

27-28. Erythraeus septemsetalis n. sp. (adult female).

56

29-31. Abrolophus welbourni n. sp. (larva).

70

32-38. Abrolophus welbourni n. sp. (larva, deutonymph

and adult female). 76

39-40. Abrolophus channingensis n. sp. (larva).

76

41-44. Charletonia curalia n. sp. (larva).

86

45-47. Balaustium nonasum (larva and adult female).

95

48-52. Balaustium nonasum n. sp. (larva and adult female).

97

53-56. new genus and new species related to Cuteria (larva).

107

56b. 57. a new genus and species related to Cuteria(larva).

107

58-60. a new genus and species retated to Cuteria (adultfemale).

109

61, 62, 64a. Allothrombium carum n. sp. (larva).

114

63, 64b-c. Allothrombium carum n. sp. (larva).

114

65a, 66, 67. Podothrombium Jucum n. sp. (larva).

122

65b, 68, 70, 71. Podothrombium Jucum (larva and adult female).

124

72-74. Podothrombium Jucum n. sp. (adult female).

128

75-78a. Calyptostoma nivalis n. sp. (larva).

136

78b-c, 79-82, 84-85. Calyptostoma nivalis n. sp. (larva, deutonymph and adult female).
138
83.
Calyptostoma nivalis n. sp. (adult female).
140
86-89. Hexathrombium bicomarum n. sp. (larva).

145

90a-c. Hexathrombidium bicomarum n. sp. (larva).

147

91. Survival rates (%) of T. auroraense at different relative humidities.

172

92. Survival rates (%) of L. sylvestratilis at different relative humidities.

172

93. Survival rates (%) of A. welbourni at different relative humidities.

173

94. Diel activity patterns of two common species.

175

INTRODUCTION

Velvet mites (Trombidioidea and Erythraeoidea: Acarina) are currently composed
of three superfamilies, six families, 18 subfamilies, 132 genera and 1018 species
worldwide (Welboum, 1987). Thirty-eight species have been described from North
America (Smiley, 1968; Treat, 1975; Treat et. al, 1979; Fain et. al, 1987; V. Grandjean,
1977; Southcott, 1988, 1991; Welboum, 1987, 1988, 1991).
Unfortunately, the classification of this group remains unsettled. VercammenGrandjean (1973) proposed six subfamilies and Robaux et. al (1976) added a seventh in
the family Trombidiidae. Southcott (1966) derived the family Chyzriidae from
Trombellidae. Vercammen-Grandjean (1973) added Protoerythraeidae to Erythraeidae.
Welboum (1987) estimated at least five families in this group. A major cause for the
taxonomic controversy is that many species have been described based on only one life
stage, either larvae or adults, so that a long list of synonyms exists for these species
(Krantz, 1978; Southcott, 1966, 1979; Treat, 1980; Welboum, 1987).
A few species have been described based on field collected adults and larvae
hatched from their eggs (Welboum, 1991; Rosa and Flechtman, 1980; Treat, 1980).
Because o f their different seasonal appearance and habitat requirements, it is often
difficult to collect all instars. More species descriptions based on all instars, or at least
on larvae and adults, are needed for accurate identification (Southcott, 1961a, b; V.
Grandjean, 1973; Krantz, 1978; Welboum, 1983, 1991).

1

2
More than 50 of the currently known 185 acarine families contain species which
have been reported as parasitic. Trombidia (excluding Trombiculidae) parasitize or prey
upon a wide variety of arthropods, including some economically important insect pests.
Host species are currently known for about 20 percent of the 1,000 named taxa. Postlarval prey are known for only 2 percent of all described Trombidia. Most genera attack
only one host order or family, and often only one genus. For some genera, it is
impossible to determine host preference as long as there is only one described species
and one host record (Welboum, 1983).
Information on feeding behavior, host selectivity of larvae, fecundity of adults,
host-parasite relations and responses to environmental variables is rare since most species
reared in the laboratory cannot be brought to oviposit (Treat, 1975; Southcott, 1946,
1961; Rosa and Flechtman, 1980; Welboum, 1991).
In North America, Treat (1975) summarized information on Leptus (Erythraeidea:
Trombidia) and their insect hosts, particularly Noctuidae, in Massachusetts. Houseweart
et al. (1980) reported that 28 percent of nearly 2,300 male spruce budworm moths,
Choristoneura Jumiferana (Clemens)(Tortricidae: Lepidoptera), collected in pheromone
traps over a 3-day period, were parasitized by larvae of two species of Leptus.
The work of Putman (1970), Cadogan and Laing (1977) and Childers and Rock
(1980) in the field and laboratory showed that Balaustium putmani Smiley, 1968
(Erythraeidea: Trombidia) were active predators of small insects and mites as well as
vegetarians feeding on plant pollen in orchards. The non-parasitic larvae, however, could
not survive in the laboratory if fed only on pollen. Adults were predators on eggs of the

3
oriental fruit moths, Grapholitha molesta (Busck)(01ethreutidae: Lepidoptera) and
Lamphygma frugiperda (Abbott and Smith)(Noctuidae: Lepidoptera) as well as other
insects and mites in North Carolina apple orchards (Childers and Rock, 1981).
Severin (1944) documented the occurrence of post-larval instars of Eutrombidium
locustarum Miller, 1934 (Trombidioidea: Trombidia) in egg chambers of grasshoppers,
where they fed on eggs. In laboratory studies, deutonymphs fed on 1 to 14 eggs, and an
adult consumed S to 20 eggs during its lifetime.
Huggans and Blickenstaff (1966) found E. locustarum to be continuously active
from May through October in Missouri, with five species of Melanoplus (Acrididae:
Orthoptera) serving as major hosts. The species was reported by Severin (1944) to
produce 1,027 to 9,542 eggs. Huggans and Blickenstaff (1966) obtained about 200,000
E. locustarum eggs in two months. Unfortunately, neither of these reports specify the
fecundity o f the species per single female. Fecundity of B. putmani, a non-parasitic
velvet mite, was reported as 175 eggs per female in up to six batches over a 20-day
period (Putman, 1970).
Treat (1975) obtained eight deutonymphs and one male adult of Leptus,
collectively comprising three undetermined species, from reared larvae attached to Oligia
exhausta (J. B. Smith)(Noctuidae: Lepidoptera). The behavior of the three deutonymphs
was recorded in detail. No other laboratory rearing of all instars of parasitic velvet mites
has been done since then.
Objectives of the present study were:
1. to identify the species of velvet mites collected in a deciduous forest in Michigan’s

4
Upper Peninsula, and to describe those which were new to science; and whenever
possible, to correlate adult, nymphal and larval stages of each species, using specimens
obtained by Project ELF and by additional field collections combined with laboratory
rearing.
2. to document life history parameters for as many species as possible, including
developmental rates, fecundity, and host preferences of parasitic larvae, through field
observations as well as laboratory experiments.

PART I. CLASSIFICATION

6
PART I. CLASSIFICATION
1. MATERIALS AND METHODS
The description of nine species is based on laboratory-reared larvae, deutonymphs
and adults, parent females of which were field collected in 1989, 1990 and 1991.
Description of the other four species is based on field-collected larvae; no post-larval
instars of these species were found. Additional specimens stemmed from samples
obtained for Project ELF, especially with respect to deutonymphs and adults.
The methods used in Project ELF included pitfall traps and extaction of litter and
soil samples (Snider & Snider, 1986, 1987). Two other methods were used to obtain mite
larvae (attached to insects) from the study site:
1). sweep net: every other day, insects were collected from bushes, trees, grasses, and
other ground vegetation around the site;
2). light traps: from mid-June to mid-August, on warm, mild nights, an auto-trouble light
was used from sundown to midnight. The light trap consisted of a 12-w light tube
suspended over a white sheet o f fabric.
In addition, hand-collecting of adults was very useful during their main period of
activity. This method was very effective along paths and edges of the forest where
ground cover was scarce.
Laboratory rearing:
Wharton (1946) showed that a mixture of plaster-of-Paris and powdered
charcoal provided the best substrate for rearing chiggers and other mites. Other
researchers (Michener, 1946; Melvin, 1946; Farrell & Wharton, 1948; Huber, 1958;

7
Lipovsky, 1953) suggested various improvements in chigger culturing techniques. The
general consensus was that a mixture of plaster-of-Paris and powdered charcoal (USP
grade) in a 9:1 by weight or 12:1 by volume ratio is best for rearing chiggers and all
other terrestrial Parasitengona. Following Dr. Snider’s suggestion for rearing Collembola
(Snider, 1973), I preferred to use a 1:1 by volume mixture, with a few grooves in the
substrate to provide a retreat for the mite or a site for egg deposition. For some species,
a piece o f moss with soil or a piece of bark was supplied as a shelter for the mites.
In the laboratory, various rearing containers were found to be adequate for mites
and their hosts. Many parasitic larvae attached to hosts were reared in glass jars with fine
screen covers. Grasshoppers and moths were kept in large insect rearing cages with fine
screen sides.
Prey for mites, particularly for deutonymphs and adults, consisted o f Collembola
and their eggs as routine food year-round, and other soft-bodied insects collected from
the site were supplied as seasonal food.
Food sources for insect hosts with mite larvae attached were different from
species to species. Water, 5% honey solution and tissue paper were provided as food and
shelter for moths, and fresh grass and water served as food for grasshoppers.
Replacement o f old food was necessary every day.
For non-parasitic larvae o f Balaustium discessus n. sp., as well as for its
deutonymphs and adults, pollen from different plant species in spring and summer was
provided. Small insects and leaf mites were used as seasonal food as well.
From spring to fall, insect rearing containers were placed in incubators at constant

8
14 ± 1.5 °C and an 8-hour light cycle. During winter, diapausing mites were placed in
a cold room at -4 ± 1.5 °C until the following spring.
Classification:
Terminology and description format follow those of Southcott (1987, 1988, 1989)
and Welboum (1983,1991). Legs were measured from coxal field to the base of pretarsal
claws. All measurements are given in micrometers. The diameter of the eyes includes
that of the lens and the surrounding rings. The "standard data" proposed by Southcott
(1961) for the scutum or prodorsal sclerite are followed. Another measurement used,
following Fain et. al. (1987), is the perpendicular distance between the base of anterior
sensillae and anterior scutum edge at the midline (ASBM). Number of dorsal idiosomal
setae of adults and deutonymphs is given as number of setae per 1000 /am, based on three
separate counts in different body areas randomly selected per mite.

2. SITE DESCRIPTION:
Characteristics of the study area discussed in 2. 1. through 2. 3. were excerpted
from Snider and Snider (1987).
2.1. Location and climatic conditions:
The study site was located in Michigan’s Upper Peninsula, Dickinson County, on
Turner Road near Channing (T44N, R29W, S25), at an altitude of approximately 420 m.
Area climate is temperate continental of the cool summer type. Yearly average
temperature is 5.4 °C, with an average high of 26 °C and an average low o f -15 °C (30year means). Annual mean precipitation is 768 mm, evenly distributed, and snowfall

9
occurs from September to May.
2.2. Soils:
The soil in the site was developed on coarse- to medium-textured glacial till, and
boulders were commonly encountered at or near the soil surface. According to the
American system (Anonymous, 1975), the soil could be classified as Alcona series (Alfic
Haplorthods, coarse-loamy, mixed, frigid), a naturally well-drained Spodosol (podzol).
Texture o f A and upper B horizons are listed in Table 1. Macronutients, organic matter
and other soil characteristics are listed in Table 2.

T able 1. Texture and thickness off the upper soil profile at the study site: m eans+SE
(N = 2 0 ).
Thickness

% sand

A

5-15, si*

58.6± 0.9

24.9+ 0.7

16.4± 0.3

B

0-12, si

58.7± 1.1

23.2 ± 1 .4

18.9± 0.3

*sl= sandy loam

% silt

% clay

Horizon

10
Table 2. Macronutrients (Kg/ha), pH and percent Organic Matter of the soil in the study
site.
variable

A horizon

Upper B horizon

PH

5.8 ±0.06

5.8±0.05

P

12.1+2.8

17.8 + 1.6

K

104.1±4.9

71.5±3.3

Ca

3120.4+152.5

Mg

245.0 ± 12.0

133.2+7.1

9.3± 0.7

2.0+0.2

% OM

1542.6+103.5

Note: means±SE, N =40 except % OM (N=10). Upper B samples taken 5 to 15 cm
below A.

2.3. Vegetation:
Based on combined understory and canopy data, Acer saccharum Marsh was
dominant, with Tilia americana L. subdominant. Among minor stand elements, Ostrya
virginiana (Mill) and Ulmus americanus L. were common in the site’s understory.
Poplars consisted mainly of Populus grandidentata Michx (Table 3).

11
Table 3. Densities and importance values (relative density + relative dominance +
relative frequency) of tree and understory species in the study site.
Importance
values

Density/2400 m2
C
US

Mean basal
area±SE
C
US

Acer saccharum

169.1

113

360

236±10 37±2

Tilia americana

62.8

47

19

367± 65 61 ± 6

Ulmus americana

26.9

3

20

189+8

Populus

21.6

-

-

-

Ostrya virginiana

9.2

1

11

-

Betula lutea

8.3

-

-

-

Prunus serotina

1.5

-

-

-

Species

spp.

40+6

66 + 14

note: C=canopy; US=understory.

The shrub association was dominated by leatherwood, Dirca palustris L. Small
poplars were also frequent at the site. Nine ground cover species were present in more
than 50 % of the 100 subplots surveyed at the site: Maianthemum canadense, sedges,
Osmorhiza

claytonii,

Polygonatum

commutatum,

Acer saccharum,

Botrychium

virginianum, Taraxacum spp., Viola pubescens and Trillium grandiflorum.

2 .4 . Host insects:
During early spring, when forest understory vegetation was still scarce,
leafhoppers, treehoppers and flies were dominant insect hosts for parasitic mite larvae.
From May to July, mosquitoes, leaf beetles, deer flies and crane flies became very
abundant. Nymphs of grasshoppers appeared in June. From late June to September,

12
several species o f Melanoplus (Acrididae: Orthoptera) served as primary hosts for four
parasitic larval mites. From early July to mid-August, several moth species and other
important insect hosts for Leptus (Erythraeidea: Trombidia) and other mites were
dominant on calm, warm summer nights. Seasonal host occurrence is listed in Table 4.

13
Table 4. Seasonal occurrence of insect hosts for velvet mites collected in the field (based
on 1990-1992 data).
Species

Common name

Host frequency

Aphis rumicis
A. forbesi
Macrosiphum
pisi
Scaphoideus
luteolus
Corythucha
ulmi
Musca sp.

aphid
aphid
aphid

principal
principal
principal

leafhopper

principal

elm lace bug

secondary

fly

secondary

Season

spring
spring
spring
spring
spring
spring

Dysaphis
plantaginea
Eriosoma
lanigerum
Phyllotreta
nemorum
Culicoides
piliferus Drosophila
melantaginea
Tipula maxima
Crambus
pedices
Grapholitha
molesta
Melanoplus
differentialis
M. confusus
M. bivittatus
A. rumicis
A. pomi
Toxoptera
piricola

apple aphid

secondary
spring

woolly aphid

secondary
spring

flea beetle

secondary

mosquito

principal

fruit fly
crane fly

principal
principal

lawn moth

principal

peach moth

principal

grasshopper

principal

grasshopper
grasshopper

secondary
secondary

aphid
aphid
pear aphid

secondary
secondary
secondary

summer
summer
summer
summer
summer
summer
summer
summer
summer
summer
summer
summer

14

Table 4. continued.
Species

Common
name

Host
frequency

Season

Melanoplus
differentialis

grasshopper

principal

Fall

M. confusus
M. bivittatus

grasshopper
grasshopper

principal
principal

Fall
Fall

Aphis rumicis
A. pom i

aphid
aphid

secondary
secondary

Fall
Fall

Muse a sp.

fly

secondary

Fall

Drosophila
melanogaster

fruit fly

secondary

Fall

15

3. RESULTS:
3.1. Systematic list of velvet mite species collected in Michigan’s Upper Peninsula:
Class Arachnida
Krantz, 1978

Order Acari formes

Lindquist, 1976

Suborder Actinedida

Krantz, 1978

Supercohort Promatides
Cohort Eleutherengonina
Subcohort Parastitengonae
Phalanx

Krantz, 1978
Krantz, 1978
Leach, 1815

Trombidia

Superfamily Trombidioidea
Family Trombidiidae
Subfamily Trombidiinae
Genus

Trombidium

T. auroraense
Subfamily Allothrombiinae
Genus Allothrombium
A. carum

n. sp.

Subfamily Podothrombinae
Genus Podothrombium
P. Jucum n. sp.

Krantz, 1978
Michael, 1884
Fabricius, 1775
Vercammen-Grandjean, 1977
Thor, 1935
Berlese, 1903
Yao, unpublished
Thor, 1935
Berlese, 1910
Yao, unpublished

16
Family Eutrombidiidae
Genus Eutrombidium
E. locustarwn
Genus Hexathrombium
H.
Family

bicomarum n. sp.

Tananpodidae

Thor, 1935
Verdun, 1909
Miller, 1934
Cooveman, 1944
Yao, unpublished
Berlese, 1902

Genus Eothrombium
E. scutelleta

Newell, 1957

Superfamily Calyptosomatoidea

Southcott, 1961

Family Calyptosomatidae

Southcott, 1961

Genus Calypstoma

Southcott, 1961

C. nivalis n. sp.

Superfamily Erythraeoidea
Family Erythraeidae

Yao, unpublished

Grandjean, 1947
Robinean-Desvoidy, 1828

Subfamily Erythraeinae

Southcott, 1957

Genus Erythraeus

Latreille, 1806

E. michiganensis n. sp.
E. septemsetalis n. sp.

Yao, unpublished
Yao, unpublished

17

Southcott, 1957

Subfamily Leptinae
Genus Leptus

Latreille, 1796

L. sylvestratilis n. sp.

Yao, unpublished

L. solitarius

Yao, unpublished

n. sp.

Subfamily Callidosomatinae
Genus Abrolophus

Berlese, 1891

A. welbourni n. sp.
A. channingensis n. sp.
Genus Charletonia
C. cularia

n. sp.

Genus Balaustium

B. kewdalli

Yao, unpublished
Yao, unpublished
Oudemans, 1910

Subfamily Balaustiinae

B. nonasum

Southcott, 1961

Yao, unpublished
Southcott, 1957
van Heyden, 1826

n. sp.

Yao, unpublished
Welbourn, 1991

A new genus and new species separated from Cuteria
Welbourn & Yao, unpublished

18
3.2. Description of species:
subfamily Leptinae:
Leptus sylvestratilis n. sp.
Type series:
Holotype: 1 larva reared from an egg deposited by a female collected from forest
floor on April 30, 1991, hatched on June 15, 1991, then attached to Melanoplus
differentialis for one day. Removed from host tarsus and mounted on slide on June
16,1991. Twenty larval paratypes reared from eggs deposited by same female. Twenty
additional larvae reared from eggs deposited by two other females collected in the same
location on May 4 and 6, 1991, hatched on June 13 and 19, 1991. Five deutonymphs and
five paratype adults reared from larvae and deutonymphs in the laboratory.
Larval description (measurements are of holotype with mean, range and number of
measured paratypes in parentheses):
Color: in life red. Idiosoma ovoid, length 320 (330,290-350,30) and width 270
(285,250-310,30); overall length from tip of mouthparts to posterior pole of idiosoma
487 (490,460-520,30) (Fig. 1).
Prodorsal sclerite (Fig. 2): with anterior margin slightly concave, anterior corners round;
shape approximately an equilateral triangle; anterolateral borders lightly convex,
posterolateral borders slightly concave; posterior pole of scutum with slight median
notch.
AW 98 (96,90-105,30); PW 125 (122,107-129,30); AM 44 (45,43-48,30); SS 73
(71,68-76,30); AL 69 (70,68-74,30); PL 75 (72,68-76,30); L 125 (127,120-131,30); W

19
127 (128,124-130,30); AAS 44 (42,39-47,30); ISD 84 (83,80-86,30); SBa 12 (12,913.30); SBp 19 (18,17-21,30); LX 31 (32,30-34,30); ASBa 19 (18,17-21,30); ASBM 12
(12,10-14,30).
Anterior trichobothria on anterior portion of sclerite. Prodorsal setae rather
clavate, with acute projecting barbs throughout most of length. AL setae arise anteriorly
and medial to PL setae. Trichobothria fine, tapering, sparsely ciliate in distal half.
Eyes 1 + 1 , cornea circular, 23 um across. Dorsal setae 54 (55,43-63,30) in length
from 53 (54,49-59,30) anteriorly to 57 (56,53-61,30) posteriorly.
Palps (Fig. 3): palpal setal formula fPp=0-B-B-BBB-6Ba>; palpal tibia with 3 B (Fig.
3a, c, d); palpal tarsus (Fig. 3b), with 5 B 19-21 in length, additional 1 B in length of
32 with basal setules at 0.23 of the tarsus, 1 w 21 at 0.23, 1 f 23 at 0.92.
Ventral idiosoma (Fig. 4): intercoxal setae between coxal field I well ciliated, 46 (47,4149.30); intercoxal setae II similar, 46 (46,45-48,30) long; 2 pairs of ciliate setae between
area o f coxal fields II-III, anterior pair 28 (27,26-29,30) in length, posterior 40 (41,3843.30) long. Posterior opisthosomal setae about 18 in number, in length of 36 (38,3640.30). Coxal field seta lb pointed, 78 (79,78-84,30) long, ciliated; seta 2b blunted,
ciliated, 34 (35,28-37,30); seta 3b blunted, ciliated, 51 (52,48-55,30).
Legs: slender, normal; leg length include trochanter and tarsus. Leg setae well setulose,
pointed and ciliated.
Leg I (Fig. 5a): length 656 (657,650-710,30); coxal field I with 1 branched seta (B) 79
(76,73-82,30) long; trochanter IB 61 (62,59-64,30); basifemur 2B 44-75; telofeinur with
5B 40-52; genu 8B 44-54,with 1 sigma (a) 38 (38,35-39,30) at 0.53 (0.50,0.49-0.55,30),

20
1 microseta (k) 3.84 (3.84,3.2-4.0,30) at 0.89 (0.89,0.87-0.92,30); tibia 14-15B 42-54,
2 phi (<f>) 33 (33,31-36,30)and 19 (19,17-21,30) respectively at 0.55 (0.53,0.51-0.55,30)
and 0.85 (0.86,0.84-0.89,30), 1 microseta (k) 7.67 (8,7-9,30) at 0.93 (0.91,0.890.95,30); tarsus 25 B 13.43-42.20, 1 omega (to) 40 (41,38-44,30) at 0.62 (0.61,0.600.64,30); 1 dorsal eupathidium (ill) 27 (25,23-27,30) at 0.93 (0.92,0.89-0.95,30) with
setules and ventral eupathidium (ip) with setules 15 (15,14-17,30) at 0.96 (0.96,0.940.99,30) respectively.
Leg II (Fig. 5b): length 552 (558,495-574,30); coxal field with IB 35 (33,30-36,30);
trochanter IB 52 (53,49-54,30); basifemur 2B 75 (75,70-77,30) and 44 (41,40-46,30);
telofemur 5B 36-56; genu 8B 58-59, no sigma seta observed, 1 k 6-9 at 0.89-0.94; tibia
15B 31-40, 2 <}>25 (23,21-25,30) and 13 (13,11-14,30) respectively at 0.11 (0.13,0.100.15,30) and 0.84 (0.86,0.83-0.89,30); tarsus 23B 13-44, 1

19 (18,17-20,30) at 0.51

(0.52,0.50-0.54,30) and 1 f 2 3 (22,20-25,30) at 0.93 (0.94,0.92-0.97,30).
Leg III (Fig. 5c): length 666 (670,650-690,30); coxal field with IB 52 (52,50-54,30);
trochanter IB 58 (58,55-60,30); basifemur IB 69 (68,67-70,30); telofemur 5B 42-45;
genu 8B 46-54, no specialized setae observed; tibia 14B 38-50, 1 ^ 31 (32,29-35,30) at
0.03 (0.03,0.02-0.03,30); tarsus 23B 19-44, 1 ip 17 (18,16-19,30) at 0.97 (0.96,0.950.98,30).
Deutonymph:
Color: in life dark red with black setae and scattered white setae. Dorsal setae
arranged densely around the edge of body segments.
Idiosoma: ellipsoid, 810 (860,810-870,20) long by 620 (650,610-660,20) wide. One eye,

21
35 (35,34-36,20) on each side of prodorsal sclerite anteriorly in a circular sclerite.
Dorsal setae range from 15,25 anteriorly to 40 posteriorly.
Prodorsal sclerite (Fig. 6): 310 (312,308-316,20) long by 30 (30,28-32,20) wide midway
between AM and ASE, with 2 pairs of trichobothria. AM 55 (56,54-56,20) with 6 setae
at the anterior end; ASE 60 (61,58-62,20).
Gnathosoma: anterior edge of gnathosoma with fingerlike fringe and approximately 30
nude setae. Anal valves with 12-16 setae (Fig. 7).
Palps (Fig. 8): palpal tibial claw entire, palpal trochanter with setae; palpal femur with
45-49 setae; palpal genu with 36-38 setae; palpal tibia with 16-18 setae; palpal tarsus
with 12-14 setae, 1 « and 5-7 eupathidia.
Legs: all legs with 2 types of setae. Most setae oriented parallel or nearly so to legs,
with small base, long setules and in length from 35 to 40. Second type eupathidial,
usually oriented perpendicular to leg with large base, short setules, and ranging in length
from 20 to 35.
Leg I: length from coxae to tarsus 930 (935,928-936,20); coxal setae 16-18; trochanter
and basifemur of all legs without solenidia. Dorsal solenidia present on all remaining
segments o f legs, except on tarsus I where they are lateral; telofemur with 2 6 on distal
area at 0.47 (0.48,0.46-0.49,20) and 0.62 (0.62,0.61-0.63,20); genu with 2

cr

dorsally

35 (35,33-36,20) and 40 (39,39-41,20) at 0.39 (0.39,0.38-0.41,20) and 0.56 (0.55,0.520.56,20) respectively, 1 a at ventral 40 (40,39-43,20) long; tibia with 4 <j>, 2 ventral
30 (31,29-32,20) and 27 (27,27-30,20) at 0.51 (0.52,0.51-0.54,20) and 0.67 (0.66,0.650.68,20), 1 dorsal 4> 40 (40,39-42,20) at 0.14 (0.14,0.13-0.15,20), and 1 lateral <f>50

22
(51,49-52,20) at 0.63 (0.62,0.62-0.64,20), 7 nude setae present on dorsal side; tarsus
with 7 dorsal u and 8 lateral «, 2 fh at 0.97 (0.98,0.96-0.99,20).
Leg II:

length 680 (685,680-692,20); telofemur with 1 B 30 (30,29-31,20) at 0.84

(0.85,0.83-0.89,20); genu with 2 a 30 (28,27-31,20) and 25 (26,24-27,20) at 0.92
(0.91,0.90-0.93,20) and 0.96 (0.97,0.96-0.98,20) respectively; tibia with 1 <f>30 (30,2932.20) at 0.81 (0.82,0.80-0.83,20); tarsus with 1 *h 35 (36, 34-37,20) at 0.94
(0.95,0.93-0.96,20), 1 fp 25 (26,24-27,20) at 0.92 (0.92,0.91-0.94,20), 1 f 16 (17,1619.20) at 0.62 (0.63,0.61-0.64,20).
Leg III: length 670 (670,668-676,20); telofemur with 4 B 22 (23,21-24,20), 16 (17,1518.20), 23 (22,21-24,20) and 14 (15,14-17,20) at 0.47 (0.48,0.46-0.48,20), 0.53
(0.54,0.52-0.56,20),0.66(0.65,0.64-0.67,20)and 0.72 (0.72,0.71-0.74,20) respectively;
genu with 1 a 32 (32,31-34,20) at 0.90 (0.91,0.89-0.93,30) and 5 nude setae; tibia with
3 0 35 (36,34-37,20), 30 (30,29-32,20) and 35 (35,34-36,20) at 0.85 (0.84,0.840.86,20), 0.83 (0.83 (0.83,0.81-0.85,20) and 0.93 (0.92,0.91-0.93,20); tarsus with 1 u
39 (39,38-41,20) at 0.89 (0.88,0.86-0.89,20) and 1 f 25 (24,23-26,20), 3 nude setae.
Leg IV:

length 975 (976,973-978,20); telofemur with 2 6 40 (40,39-43,20), and 40

(40,39-42,20) at 0.50 (0.50,0.49-0.52,20) and 0.81 (0.81,0.80-0.83,20); genu with 4 a
35 (36,34-36,20), 40 (40,39-42,20), 30 (31,29-32,20); 45 (45,44-46,20) at 0.52
(0.52,0.51-0.53,20), 0.75 (0.75,0.74-0.76,20), 0.82 (0.82,0.81-0.83,20) and 0.89
(0.88,0.87-0.90,20) respectively; tibia with 1 <f> 30 (30,29-31,20) at 0.85 (0.84,0.830.86,20); tarsus 2 w 35 (35,34-37,20) and 44 (45,44-46,20) at 0.86 (0.85,0.84-0.87,20)
and 0.89 (0.88,0.87-0.90,20).

23
Adult female:
Color: in life dark red with black setae and scattered white setae on dorsal
idiosoma.
Idiosoma:

ellipsoid, 1075 (1100,1035-1200,5) long and 930 wide (970,920-1000,5).

One eye 40 (40,39-42,5) in diameter at each side of prodorsum. Most dorsal setae catkin­
like,well setulose, length from 12 to 25 anteriorly, and 12 to 28 posteriorly. Genital
valves with 57-64 setae; anal valves with 10 setae (10,8-12,5)(Fig. 9).
Prodorsal sclerite (Fig. 10): 375 (378,370-380,5) long and 10 (10,10-12,5) wide midway
between AM and SS. AM 35 (35,34-37,5) long and SS 87 (84,83-88,5) long with 4-6
setae at the anterior end.
Gnathosoma: anterior end with fingerlike fringe and 30-40 nude sensory setae. Four
long nude setae located at each side, 37 to 40 in length.
Palps (Fig. 11): palpal trochanter with 8-10 setae; palpal femur with 74-76 setae and 3
microsetae; palpal genu with 58-62 setae and 1 a\ palpal tibia with 10-12 setae, 3 </>and
5 microsetae, tibial claw entire; palpal tarsus with 8B, 2 o> and 18-20 eupathidia at
anterior area o f tarsus.
Legs: all legs with setulose setae, oriented parallel to leg, covering most areas of legs;
eupathidial setae oriented perpendicular to leg segments.
Leg I: 1300 (1320,1180-1460,5) in length; basifemur with 1 6 50 (5l,50-53,5)at 0.73
(0.74,0.73-0.76,5); telofemur with 3 0 45 (45,44-46,5), 30 (31,29-33,5), 35 (36,34-36,5)
at 0.49 (0.48,0.47-0.49,5), 0.80 (0.79,0.78-0.81,5)and 0.82 (0.81,0.81-0.83,5), 5 nude
setae; genu with 6 a 30 (30,30-32,5), 50 (52,50-53,5), 40 (40,39-41,5), 50 (50,50-52,5),

24
40 (40,40-43,5) and 30 (30,30-32,5)at 0.22 (0.21,0.20-0.25,5),0.52 (0.52,0.51 -0.54,5),
0.67 (0.66,0.65-0.68,5), 0.78 (0.78,0.77-0.80,5), 0.80 (0.81,0.79-0.83,5) and 0.91
(0.90,0.90-0.93,5); tibia with 9 <M5 (46,45-47,5),35 (35,34-36,5), 25 (25,25-27,5), 35
(36, 34-36,5), 25 (25,25-26,5), 50 (50,50-51,5), 50 (49,48-51,5), 45 (45,45-46,5) and
40 (40,40-42,5) at 0.18 (0.18,0.18-0.19,5), 0.27 (0.26,0.25-0.27,5), 0.33 (0.32,0.310.34,5), 0.54 (0.55,0.54-0.56,5), 0.64 (0.64,0.63-0.65,5), 0.71 (0.70,0.70-0.72,5), 0.89
(0.90,0.89-0.91,5), 0.95 (0.95,0.94-0.96,5) and 0.96 (0.96,0.95-0.97,5) and 0.96
(0.96,0.96-0.97,5) respectively, 1 k present and 4 nude setae; tarsus with 10 scatted u
and 1-4 ft
Leg II:

length 905 (910,850-930,5); basifemur with 1 0 30 (30,28-32,5) at 0.68

(0.67,0.67-0.69,5); telofemur with 2 0 28 (28,27-29,5) and 32 (31,30-32,5) at 0.46
(0.45,0.45-0.47,5) and 0.90 (0.89,0.89-0.90,5); genu with 5 a 25 (25,24-26,5), 25
(25,25-26,5), 32 (31,30-32,5), 26 (25,25-27,5) and 35 (35,35-37,5) at 0.19 (0.18,0.170.19,5), 0.57 (0.56,0.55-0.57,5), 0.91 (0.90,0.90-0.92,5), 0.87 (0.86,0.86-0.89,5), and
0.96 (0.95,0.95-0.97,5); tibia with 4 <f>25 (25,25-26,5), 24 (24,24-26,5), 25 (25,25-26,5)
and 38 (37,37-38,5) at 0.27 (0.27,0.26-0.28,5), 0.45 (0.46,0.45-0.46,5), 0.84
(0.83,0.83-0.85,5) and 0.95 (0.94,0.94-0.96,5) respectively; tarsus with 2 w distally 23
(22,22-23,5), 19 (19,18-19,5)at 0.80,0.80-0.82,5)and 0.81 (0.81,0.81-0.82,5), 2 fh 32
(31,31-32,5) and 39 (38,37-39,5) at0.81 (0.81,0.81-0.83,5)and 0.94 (0.94,0.94-0.96,5),
1 ft) 23 (22,22-24,5) at 0.97 (0.97,0.97-0.98,50.
Leg III: length 940 (930,900-940,5); basifemur without 0; telofemur with 3 0 45 (45,4550,5), 30 (30,30-33,5), and 45 (45,45-46,5)at 0.50 (0.50,0.49-0.50,5), 0.57 (0.56,0.55-

25

0.57,5), 0.86 (0.85,0.85-0.86,5); genu with 1 a 35 (35,35-36,5) at 0.90 (0.90,0.900.92,5); tibia with 2 0 40 (38,36-42,5),35 (35,35-37,5) at 0.43 (0.44,0.43-0.46,5), 0.72
(0.71, 0.71-0.74,5); tarsus with 2 fh 40 (40,39-42,5), 45 (46,44-47,5) at 0.75
(0.74,0.72-0.75,5)and 0.89 (0.89,0.89-0.91,5) respectively, 1 ft) 30 (30,30-32,5) at 0.93
(0.92,0.90-0.93,5).
Leg IV: length 1685 (1687,1680-1695,5); basifemur with 1 0 55 (56,54-56,5) at 0.79
(0.79,0.78-0.80,5); telofemur with 2 0 45 (48,45-50,5) at 0.89 (0.88,0.88-0.90,5), 50
(51,50-52,5) at 0.39 (0.38,0.37-0.39,5); genu with 4 a 35 (35,35-37,5), 55 (56,55-57,5),
45 (46,45-47,5), and 60 (60,59-62,5) at 0.24 (0.24,0.23-0.25,5), 0.47 (0.47,0.460.48,5), 0.54 (0.54,0.54-0.56,5), and 0.87 (0.87,0.86-0.88,5) respectively; tibia with 5
0 55 (56,55-57,5), 45 (46,45-47,5), 50 (50,50-51,5), 40 (40,40-41,5), 50 (50,50-52,5)at
0.48

(0.47,0.46-0.48,5),0.61

(0.61,0.60-0.63,5),

0.62

(0.63,0.62-0.64,5),

0.87

(0.87,0.87-0.89,5) and 0.93 (0.93,0.92-0.95,5); tarsus with 1 cj 28 (29,28-29,5) at 0.93
(0.94,0.93-0.95,5), 2 fti 39 (38,38-39,5), 55 (56,54-56,5) at 0.71 (0.72,0.70-0.73,5) and
0.92 (0.92,0.91-0.93,5), 1 ft) 40 (41,40-43,5) at 0.90 (0.90,0.89-0.91,5).
Etymology:
The specific epithet is derived from sylvestra-, meaning "forest", and tilis,
meaning "found in", which characterized this forest-dwelling species well.
Distribution o f types:
The holotype, 20 larval and 5 adult female paratypes are in Department of
Zoology, Michigan State University, East Lansing, MI. One larval, and one adult female
paratypes will be deposited in each of the following institutions: Field Museum of

26
Natural History, Chicago, IL; British Museum (Natural History), London, U. K.; and
Shanghai Museum of Natural History, Shanghai, PRC.

27

Figs. 1-11. Leptus sylvestatilis n. sp. (larva, deutonymph and adult female):
1. dorsal idiosoma;
2. prodorsal sclerite;
3a-d. palpals;
4. ventral idiosoma;
6. prodorsal sclerite and eyes of deutonymph;
7. anal valves o f the nymph;
8. nymph palpais;
9. adult genital and anal valves;
10. adultal sclerite;
11. adult palpais.
Scale lines for Figs. 1, 3a, 6, 7, 8, 9, 10, 11 each represent 100 pm \ scale lines for
Figs. 2, 3b, c, d, 4a each represent 50 pm.

28

29
Leptus solitarius n, sp.
Type series:
Holotype: 1 larva collected from a moth, Apamea lignicolora Guenee, on August
5, 1991. Thirty paratypes collected from other moths, crab spiders, and other insects
from early July to late August in 1990 and 1991. Five deutonymphs and five adults were
reared from the larvae attached to these hosts.
Larval description:
Idiosoma (Fig. 14):
Color:

in life yellow. Holotype 595 (863,590-930,30) long by 385 (492,385-

560.30) wide; 1 eye 21 (23,21-26,30) on each side of prodorsal sclerite with a circular
sclerite around. Length from tip of mouthpart to pole of idiosoma 770 (919,5701245.30). Number of dorsal setae 102 (98,87-106,30) in length from 44.12-47.95
anteriorly to 46.03-55.62 posteriorly (Fig. 12a, b).
Palpal setae formula (Fig. 13): palpal femur and palpal genu with 1 B seta each, palpal
tibia with 3 B stae and 1 tibia claw, palpal tarsus with 5 B setae, 1 nude seta, 1 a> and
1 f. Palpal setae formula = 0-B-B-BBB-5BNcof in length of 86-61-25,38-17-33 (0.23),
21 (0.68)-21 (0.23)-23 (0.92).
Prodorsal sclerite (Fig. 14): anterior comers pointed, anterior margin straight, posterior
margin concave (Fig. 18). Standard data listed in Table 5.
Leg I (Fig. 15a): length 765 (787,745-836,30) from trochanter to pretarsal claw, coxal
field I with IB 96 in length (96,93-98,30); trochanter with IB 75 (75,72-80,30);
basifemur with 2B 86 (87,82-89,30), 111 (108,103-116,30); telofemur with 5B 59-76,

30
genu with 8B 63-88, 1 a 42 (40,38-44,30) at 0.50 (0.50,0.47-0.54,30), 1 k 6 (6,5-8,30)
at 0.93 (0.94,0.90-0.96,30); tibia with 14B 34-69, 2 0 36 (35,32-37,30) at 0.05
(0.05,0.03-0.06,30), 23 (22,20-25,30) at 0.87 (0.86,0.83-0.88,30); tarsus with 23-25B
55.6-65 in length posteriorly, and 32-40 in length anteriorly, 1 cj 40 (41,38-43,30) at
0.54 (0.52,0.49-0.56,30), 1 fh 23 (24,21-26,30) and 1 {p 17 (17,16-18,30) at 0.93
(0.92,0.90-0.94,30).
Leg II (Fig. 15b): length 769 (770,750-820,30) from trochanter to pretarsal claw, coxal
field II with IB 34 (34,30-36,30); trochanter with IB 67 (68,66-70,30); basifemur with
2B 100 (96,93-100,30) and 94 (93,90-96,30); telofemur with 5B 59-73; genu with 8B 6190 in length, no a setae observed but 1 k 6-8 at 0.91-0.94; tibia with 14B 34-36
anteriorly,67-78 posteriorly, 2 (j> 36 (36,34-37,30) at 0.05 (0.05,0.03-0.06,30), 23
(21,18-24,30) at 0.87 (0.85,0.83-0.88,30); tarsus with 25B 40-45 anteriorly, 67-73
posteriorly, 1 u 23 (24,22-26,30) at 0.47 (0.48,0.46-0.52,30), 1 fh 23 (23,22-25,30) at
0.91 (0.92,0.90-0.94,30) and 1 ip 19.18 (19,18-22,30) at 0.98 (0.96,0.95-0.99,30).
Leg III (Fig. 15c): length 853 (855,847-870,30); coxal field with IB 54 (55,52-56,30);
trochanter with IB 67 (68,66-70,30); basifemur with 2B 100 (98,96-101,30) and 94
(95,93-96,30); telofemur with 5B 63-73; genu with 8B 61-90 in length; tibia with 14B
38-45 anteriorly and 65-80 postiorly, 1 <f>36 (36,35-38,30) at 0.04 (0.05,0.03-0.06,30);
tarsus with 22-23B 24-30 anteriorly and 59-71 posteriorly, 1 fp 17.26 (18,16-20,30) at
0.96 (0.97,0.95-0.98,30).

31
Deutonymph:
Color: in life brown. Idiosoma 836 (877,736-922,5) long by 504 (527,482-544,5)
wide. Dorsal setae 25-38 in length, ventral setae 33-38 long. Anal valves 60 (62,57-65,5)
with 6 setae 31-33 long at each side (Fig. 16).
Prodorsal sclerite (Fig. 17): 283 (293,274-311,5) long by 36 (37,32-39,5) wide; AW

46 (47,43-50,5) with 6 setae at front end 46-50 long; SM 69 (70,67-73,5), SS 102
(104,100-113,5), SBa 13 (14,12-15,5), SBp 13 (13,12-15,5), LX 59 (61,57-64,5), ISD
249 (252,237-273,5). Eyes 1 + 1 27 across.
Leg I:

965 (973,886-985,5), coxal field 225 (228,217-236,5); trochanter 96 (97,94-

98.5); basifemur 117(121,113-132,5); telofemur 157 (153,147-168,5) with 1-2 6 at 0.380.85; genu 198 (201,188-212,5) with 4 a at 0.44-0.88; tibia 219 (221,211-243,5) with
11-12 <f>at 0.12-0.91, and 1 k at 0.89-0.92; tarsus 178 (182,165-193,5) with 12-15 coat
0.79-0.94 and 2 fh 47.95 each at 0.94 and 0.97 respectively.
Leg II:

646 (658,637-729,5), coxal field 184 (188,172-198,5); trochanter 71 (72,70-

74.5); basifemur 100 (102,97-108,5); telofemur 102 (105,100-112,5) with 1 6 at 0.860.88; genu 142 (144,138-155,5) with 2 a at 0.88-0.91, without k; tibia 144 (150,136162.5) with 4-5

at 0.12-0.85; tarsus 88 (89,85-91,5) with 1 iti 35 (35,32-36,5) at 0.91

(0.92,0.90-0.94,5), no w observed.
Leg III: 716 (722,708-735,5), coxal field 125 (126,118-135,5); trochanter 77 (78,7580.5); basifemur 102 (105,101-110,5); telofemur 105 (107,102-115,5) with 3 6 at 0.260.87; genu 165 (168,157-176,5) with 3 a at 0.45-0.85, without k; tibia 171 (174,166182.5) with 1-2 0 at 0.81-0.84, 2-3 nude setae at 0.08-0.24; tarsus 96 (97,93-98,5) with

32
1 fh 38 (38,36-39,5) at 0.90 (0.91,0.89-0.93,5), 1 dorsal f a t 0.79-0.83, no to observed.
Leg IV:

955 (948,932-975,5), coxal field 225 (230,220-243,5); trochanter 92 (94,92-

96.5); basifemur 129 (132,119-142,5); telofemur 152(157,148-166,5) with 3-4 0 at 0.110.86; genu 227 (233,221-238,5) with 2-3 <rat 0.53-0.91, 8 nude setae at 0.53-0.84 dorsal
area; tibia 237 (247,228-253,5) with 1 <j>at 0.16-0.19; tarsus 118 (122,115-133,5) with
1

38.36 (39,35-40,5) at 0.89-0.92, without u.

Adult female:
Color: in life brown with black setae as well as white scattered setae. Idiosoma
from the tip of mouthpart to posterior pole 2250 (2475,2138-2755,5) long by 1523
(1623,1477-1738,5) wide. Dorsal setae 54-56 in length; ventral setae 27-38, anal valves
84 (86,83-90,5) with 25-27 setae 33-38, genital valves 443 (452,433-468,5) with 87-102
setae (Fig. 18).
Prodorsal sclerite (Fig. 19): 573 (582,566-611,5) long by 77 (78,74-90,5) wide; AW
81 (82,80-85,5) with 8 setae at the front edge 61-73 long; SM 111 (115,108-121,5); SS
148 (152,138-162,5); SBa 31 (31,30-34,5); SBp 31 (32,30-35,5); ISD 451 (457,438477.5); LX 88 (90,86-93,5).
Leg I:

1924 (1986,1877-1997,5), coxal field 264 (267,255-285,5); trochanter 146

(144,138-157,5); basifemur 347 (355,328-389,5) with 1 0 at 0.66-0.70; telofemur 320
(325,307-355,5) with 5-6 0 at 0.65-0.72; genu 384 (394,366-410,5) with 6-7 a at 0.580.93; tibia 368 (377,352-410,5) with 8-9 <t>at 0.17-0.89, 19-20 nude setae at 0.23-0.76;
tarsus 359 (363,344-382,5) with 8-11 u at 0.80-0.93, 2 dorsal f at 0.76-0.81, 1 dorsal
f a t 0.37-0.42, 4 fh at 0.94-0.99, 7 ventral f a t 0.16-0.96, 29-32 fumulus at 0.18-0.91,

33
majorly distributed at one side, many small setae with big bases at the other side.
Leg II:

1234 (1263,1187-1435,5), coxal field 241 (244,237-253,5); trochanter 150

(154,142-163,5); basifemur 146 (152,137-162,5) with a long seta at 0.78-0.83; telofemur
209 (212,207-228,5) with 1 0 at 0.81-0.84; genu 272 (279,263-297,5) with 3-4 a at 0.050.91, 7-8 nude setae at 0.24-0.84; tibia 274 (278,265-294,5) with 4-5 <f>at 0.53-0.96, 6
nude setae at 0.27-0.72; tarsus 184 (187,176-193,5) with 1-2 w at 0.74-0.78, 4 fumulus
at 0.29-0.45, 2 f a t 0.85-0.95, 2-3 fp at 0.90-0.97.
Leg III:

1306 (1327,1284-1359,5), coxal field 227 (228,217-233,5); trochanter 129

(132,122-136,5); basifemur 167 (172,158-180,5); telofemur 205 (207,202-214,5) with
1 0 at 0.92-0.95; genu 300 (306,287-311,5) with 3-4 a at 0.78-0.94; tibia 309 (314,302327,5) with 3-4 0 at 0.50-0.88, 4-5 nude setae at 0.16-0.56; tarsus 196 (196,193-204,5)
with 1-2 to at 0.67-0.86, 2 fumulus at 0.28-0.87, I fh at 0.94-0.97, 2-3
Leg IV:

at 0.90-0.97.

2083 (2064,2033-2185,5), coxal field 260 (266,257-271,5); trochanter 155

(158,153-162,5); basifemur 326 (332,318-341,5) with 1 0 at 0.91-0.93; telofemur 362
(369,347-383,5) with 2-3 0 at 0.74-0.92; genu 451 (455,438-472,5) with 4-5 a at 0.230.94, 3-4 nude setae at 0.35-0.49; tibia 453 (458,442-473,5) with 3-4 <f>at 0.29-0.87, 5-6
nude setae at 0.11-0.38; tarsus 336 (341,328-355,5) with 2 fh at 0.89-0.94, no

oj

and

fumulus observed.
Etymology:
The species name solitarius is derived from a Latin word meaning lonesome.

34

Fig. 5a-c. Leptus sylvestratllis n. sp. (larva): leg I-III from genu to tarsus. Scale line for
the Figure is 50 pm.

Figs. 12-14. Leptus solitarius (larva):
12a, b, dorsal and ventral idiosoma;
13a, b, c, d gnathosoma and palpais;
14. prodorsal sclerite.
Scale lines for Figs. 12a, b, 13a represent 100 pm; scale lines for 13b, c, d and 14 each
represent 50 pm.

36

Figs. 15-19. Leptus solitarius n. sp. (larva, deutonymph and adult female):
15a-c. leg I-I1I from genu to tarsus (larva);
16. anal valves (nymph);
17. prodorsal sclerite (nymph);
18. genital and anal valves (female);
19. prodorsal sclerite (female).
Scale lines for Fig. 15a-c, 16, 17, 18, 19 each represent 100 /im.

37

\y
15.

38
Distribution of Types:
The holotype, 20 larval, 20 deutonymphal and 5 adult female paratypes are in
Department of Zoology, Michigan State University, East Lansing, MI. One larval,
deutonymphal and female paratype will be deposited in each of the following institutions:
Field Museum of Natural History, Chicago, IL; British Museum (Natural History),
London, U. K.; Shanghai Museum of Natural History, Shanghai, PRC.
Discussion:
Based on data published in many papers, some acarologists use the number of leg
solenidia as a major feature to split the genus into four or five groups (Table 5). Other
characters, such as the number of solenidia on the palpal genu, are also considered
additional criteria for identification.
Differences between the two species of Leptus in Michigan’s UP and the other
five known north and central American species are listed below (Table 6).
It is not difficult to separate L. sylvestratilis from L. neariicus since shape, size
and other prodorsal sclerite characters, number of both dorsal and ventral setae, length
of legs and specialized leg setae differ significantly (Table 6). Leptus sylvestratilis differs
from L. ariel in having two sensory setae on tibia I instead of one, and a square sclerite.

39
Table 5. Morphological features of five groups of Leptus larvae (adapted from Beron,
1975; Fain et al, 1987).

leg/group

group I

group II

group III

group IV

group V

genu

Ge I 5 a

Ge I 2 or 5 a

Ge I,II each 1 a

Ge lino a

Gel la

tibia

Ti 1 1 0

Ti I 3,5,7 0

Ti I,II each 1 0

Ti I,II 20

Til 30

no. sp.

1

3

1

many

1

The species also differs from L. treati by the combination o f following characters:
1). anterior comers of the sclerite round, anterior margin almost straight, posterior pole
not concave; 2). number o f dorsal setae less than that of L. tread;
3). AL, PL sclerite setae shorter than those of L. treati', 4). deutonymph and adult differ
from L. treati in having white patches of setae; 5). host preference differs from L. treati
in that L. sylvestratilis parasitizes several species of grasshoppers instead of the spruce
bud worm.

Table 6. Morphological differences between two UP Leptus and five other Leptus in America

treati
Holo. x

sylvestratilis
Holo. x

solitarius
Holo. x

80
82
91
93
42
41
61
60
70
75
80
75
96
93
105 108
101 105
12 11.5
15
15
18
16
28
25
28
31

82
99
40
68
63
75
53
86
107
15

97
124
44
72
69
74
84
124
126
11
19
44
6
11

94
105
51
69
71
78
67
118
120
13
17
13
13
40

-

94

-

73 68

54 55

102 98

34

_

38

-

31 -

26 26

34

906
735
921

-

ariel
*Holo. x

clarki
Holo. x

AW
PW
AM
SS
AL
PL
ISD
L
W
SBa
SBp
A-P
ASBM
AAS

80
96
38
55
49
55
58
85
105
11
12
14
9
34

82
94
35
53
49
54
57
82
103
11
13
15
9
35

96 96
112 112
70 75
82 79
65 62
60 56
57 59
91 91
125 127
13 15
18 17
16 17
9 9.5
42 40

82
100
51
81
88
86

DS

49

-

102 -

82

VS

20 -

32 -

leg length
I
II
III

501 507 584 -

772736 897 -

Character/sp

indianensis
Holo. x

-

82
100
-

-

-

-

-

-

-

-

-

-

-

-

-

*

-

-

nearcticus
Holo. x

664 723
644 679
742 793

-

79
92
42
72
61
72
58
94
100
12
-

18 17
-

-

-

-

538 539
526 516
601 609

96
86
30
50
42
49
58
87
86
9
9
12
-

27

655 552 665 -

765
769
853

64
77
33
49
51
62
51
91
84
26
11
-

6
28

36

-

Table 6. (cont’d).
clarki
X

indianensis
X

genu a

I IIIII
1 - -

I 11 III
1 - -

I I I III
1- -

I 11 III
1 - -

I II III
1 - -

I IIIII
1 - -

i u rn
i - -

tibia <f>

1 2 1

2 2 1

32

2 2

2 2 1

2 2 1

2 2 1

B setae
Tf
Ti
Ta

4 5 5
14 15 14
22 20 20

4 5 5
14 15 13
23 22 18

5 5 5
14 15 15
25 23 23

5 5 5
14 15 14
25 23 23

5 5 5
14 15 15
24 21 24

Host &
Location

bees
Guatemala

spruce moth
MA

grasshoppers
MI

nearcticus
X

treati
X

sylvestratilis
X

solitarius
X

ariel
X

Character/sp
solenidia

ants
ID

-

1

- -

. . .
-

- -

opilionids
IN

1

5 5 5
14 16 16
26 30 30
opilionids
IN

moths etc.
MI

42
The morphology o f L. solitarius is similar to the description of L. ignotus (Beron,
1967) in many features, such as scutum shape, host preference, number of setae between
coxal field III and characters of palpals. However, some important features separate the
species from ignotus: longer legs, more dorsal setae, larger scutum and presence of some
specialized setae (Table 7).

Table 7. Major differences between L. ignotus and L. solitarius: leg length, number of
solenidia and dorsal setae, and measurements of sclerite.
Species

Solenidia

Legs
1

2

3

Ge
12 3

Ti

Ta

12 3

12 3

Dorsal
setae

Sclerite
AW PW L W

ignotus

515 505 555

1 1-

2 2 1

11-

73

74

85 92

solitarius

765 769 853

1- -

22 1

11-

116

94

105 118 98

96

The larvae of the genus were described from Europe in 1763 by Berlese under
various generic names, such as Acarus L., 1758, Phyncholophus Duges, 1834 and
Achorolophus Berlese, 1891 (Oudemans, 1929,1937; Southcott, 1961). The first
European larval Leptus described which now can be recognized is Leptus ignotus by

43
Oudemans, 1903. Between 1902 and 1911, Oudemans described 11 species of Leptus
larvae worldwide (classified in Achorolophus), including some North American
specimens placed in Leptus ignotus. In 1914, he stated that he had examined hundreds
of specimens of this species, which he synonymized with L. opilionis (O. F.
Muller, 1776) from Denmark and L. phalangii (de Geer, 1778). He also proposed a
further provisional synonymy with Pediculeus coccineus Scopoli, 1763 from Yugoslavia.
He also regarded a species described as L. groenlandicus Tragardh, 1904 from Greenland
as a synonym of ignotus.
Evans (1910) and Bruyant (1911) indicated that larvae parasitizing Phalangida in
Scotland and France respectively could be placed in Leptus, but since there was still
some confusion, the generic name Achorolophus Berlese, 1891 continued to be used for
these larvae for a number of years. Paoli (1937) described Achorolophus dubius as a
parasite of acridid Orthoptera and a bombyliid dipteran from Italy.
Turk (1945) described Leptus (Achorolophus) killingtoni from several species of
Odonata in England. Schweizer (1951) referred some larvae from Switzerland to
"Achorolophus ignotus". Andre (1953) described an ectoparasitic mite of scorpions in
France as L. pyrenaeus. In 1956, Feider reported L. phyllotretae as an ectoparasite of
Chrysomelidae (Coleoptera) in Romania. He described L. galerucae, an ectoparasite of
Curculionidae and other Coleoptera, and succeeded in rearing a deutonymph.
Beron (1967) (Bulgaria) described six new species: L. echinopus on Collembola,
L. josifovi on Coreidae (Heteroptera), L. meloidarum on Meloidae (Coleoptera), L.
orthopterarum on Tettigoniidae (Orthoptera), L. slivovi on Lymantriidae (Lepidoptera)

44

and L. southcotti on CoIIembola. He assigned another species to L. ignotus (Oudemans)
and reclassifed it as L. holmiae n. sp. Haitlinger (1987) described three new species
from Poland: L. clethrionomydis on a rodent, L. mariae (free-living) and L. zbelutkaicus
(free-living). He later identified the last as a synonym of L. ignotus (Oudemans).
Treat (1975) recorded many specimens as ectoparasites of Lepidoptera, chiefly
Noctuidae, and commented that there were at least three different species. Fain et al.
(1987) described two species from Indiana, USA as ectoparasites of Phalangida: L.
indianensis and L. nearcticus. Southcott (1989) described L. ariel from Guatemala,
ectoparasitic on the European honey bee, Apis mellifera L.; another North American
species, L. clarki, was also described by him as an ectoparasite upon a harvester ant in
the same year.
Welboum (1990) described an ectoparasite of a spruce budworm moth, L. treati
from both larvae and adults, but in 1991, Southcott redescribed it and named it L.
welbourni. About 90 species of larval Leptus have been described on a world basis since
1900. Many adults of the species have also been described since before 1900. In only a
few instances have correlations between larvae and post-larval instars been made (Evans,
1910; Bruyant, 1911; Southcott, 1946,1961 ;Feider, 1967; Treat, 1975; Welboum, 1991).
In 1992, Southcott revised 18 European and 17 North American species from
larvae and nymphs, but some of the data he used for identification still are not sufficient
to key out species correctly. Further efforts are necessary since adequate standards and
information on the correlation between larvae and adults is still rare.

45

Key to the larval Leptus o f the Americas (modified from Southcott, 1991)
1. Palp genu with two setae. Posterolateral scutal setae (PL) off scutum
.................. L. lomani (Oudemans, 1902)(Chili)
Palp genu with one seta. PL not off scutum......................................................................2
2. Genu I with 5 a ........................................................................................................................ 3
Genu I with 1 a or no a ......................................................................................................... 4
3. Genu II with 1 a. Telofemur I without solenoidalae
L. stieglmayri (Oudemans, 1905)(Brazil)
Genu II without a. Telofemur I with 3 solenoidalae
.................L. schedingi (Oudemans, 1905)(Chili)
4. Genu I without a

L.gagzoi (Oudemans, 1901)(Panama)

Genu I with l a ........................................................................................................................ 5
5. Tibia I with 3 0

L. indianensis Fain et. al,1987(Indiana,USA)

Tibia I with 1 o r 2 <t>............................................................................................................... 6
6. Genu II with 1 a .......................................................................................................................7
Genu II without a ..................................................................................................................... 8
7. AL scutalae longer than shield width. Two ventral idiosomal setae between coxae III
................................. L. oudemansi (Karppinen,1958)(Surinam)
AL scutalae about half as long as shield width. Four ventral setae in area between
coxae II and III.
Tibia I with 1 sotenoidala.................................... L.sieversi (Oudemans, 191 l)(Venezue!a)
8. Dorsal setae about 50............................................................................................................... 9

46
Dorsal setae more than 70.............................................................................................. 10
9. Dorsum with 44 setae, length of legs more than 1000 /xm. AL,PL setae not at equal
length, 49 and 55 /xm seperately, parasite of honey bee
..................... L. ariel Southcott 1989 (Guatemala)
Dorsum with 50 setae, length of legs more than 400 /xm, AL, PL setae 47 and 51 /xm
seperately, parasite of grasshoppers
L. sylvestratilis n. sp. (Michigan,USA)
10. Dorsum with 73 setae, anterior comers of sclerite pointed, PW 92 /xm, PSE seta 72
/xm, parasite of spruce moths..........................L. treati Welboum 1991 (Maine,USA)
Dorsum with 99 setae, anterior comers of sclerite round, PW 78 /xm, PSE seta 54
/xm, parasite of moths........................................L. solitarius n. sp. (Michigan, US A)
Dorsum with 94 setae, anterior comers of sclerite pointed, PW 96 /xm, PSE seta 62
/xm, parasite of opilionids...........................L. nearcticus Fain et al. 1987 (Indiana,USA)
Dorsum with 102 setae, anterior comers of sclerite round, PW 112 /xm, ASE, PSE
70 and 80 /xm in length seperately, parasite of ants
................................... L.clarki Southcott 1989 (Idaho,USA)

47
Subfamily Erythraeinae:
Erythraeus michiganensis n. sp.
Type series:
Holotype: 1 larva hatched on July 4, 1991 from eggs deposited by a female
collected on the forest floor on May 20, 1991. Fifteen paratypes hatched on July 4, 5,
and 7, 1991 from the egg mass deposited by the same female. Additional 15 paratypes
hatched on July 30, 1991 from eggs laid by other females collected in same location.
Five deutonymphs were laboratory reared from larvae and five adults collected at Turner
Road, Channing.
Larval description:
Color: in life yellowish-brown. Idiosoma ovoid, 587 (634,544-820,30) long by
322 (425,310-526,30) wide between leg II and 348 (368,310-428,30) wide between leg
III (Fig.20a). Eyes 2 pairs set on each side of dorsal cupules, anterior one 19 (19,1721.30) long by 21 (21,19-23,30) wide, posterior eye 17 (18,16-19,30) by 17 (17,lb19.30) wide (Fig. 20c). Dorsal setae 57-59, anterior setae 59-73 in length, 77-82 at
posterior region (Fig. 20d). One pair (la) 79 (79,75-82,30) of intercoxal setae between
coxal field leg I,and 1 pair (3a) between coxal field leg III, 58 (58,56-62,30); seta lb on
coxal field leg I, 111 (123,108-131,30); coxal field leg II and III each with 1 seta (2b
and 3b) in 69 (72,65-75,30) and 75(75,72-76,30) respectively; after coxal leg III, 21
(22,20-25,30) ventral setae, 54-63 anteriorly and 50-69 posteriorly (Fig. 20b).
Prodorsal sclerite (Fig. 21): anterior margin slightly concave at the middle, posterior pole
sharply concave. AW 42 (43,40-44,30); PW 88 (89,85-94,30); W 148 (152,138-167,30);

48
L 102 (105,98-108,30); ASE 57.54

(58,56-60.30); PSE 90 (92,87-94,30); AL 109

(110,105-117,30); A 61 (62,59-64,30); AAS 15 (16,13-17,30); SBa 12 (12,11-14,30);
SBp 13 (14,12-15,30); PL 88 (89,85-92,30); ASBp 23 (23,21-25,30); ASBa 31 (32,2934.30); ASBM 8 (8,5-9,30); LX 23 (23,20-24,30); ISD 63 (64,62-65,30).
Gnathosoma (Fig. 22a, b, c, d): palpal setal formula fPp=0-B-B-BBB-5B2Nwf; palpal
tibial claw 2 pronged; palpal tarsus with 2 nude setae, 1

cj

13 (14,12-15,30), 1

eupathidum 40 (41,40-44,30) with 1 companing seta, 5 barbed setae 27-31, including 1
long seta 69.
Leg I (Fig. 23a): 1126 (1204,1067-1320,30); coxae 82 (83,80-85,30) with IB;
trochanter 84 (86,82-87,30) with IB 92 (94,90-96,30); basifemur 165 (168,159-172,30)
with 3B 73-77 anteriorly, 105-109 posteriorly; telofemur 146 (153,143-165,30) with 5B
86-88 posteriorly and 79-92 anteriorly; genu 226 (238,221-244,30) with 8B 86-100
posteiorly and 84-90 anteriorly, 1 a 27 (27,24-30,30) at 0.62 (0.60,0.58-0.64,30), 1 k
6 (6,4-7,30) at 0.93 (0.95,0.92-0.97,30); tibia 300 (312,287-338,30) with 16B 86-93
long, 2 $ 26 (27,24-29,30) and 27 (27,25-29,30) at 0.58-0.90, 1 k 6 (6,4-7,30) at 0.94
(0.95,0.92-0.97,30); tarsus 162 (165,157-174,30) with 18-19B 78-94 long, 1

17

(17,15-19,30) at 0.63 (0.62,0.60-0.66,30), 1 f t 25 (26,23-28,30) at 0.93 (0.94,0.920.97,30).
Leg II (Fig. 23b): 1007 (1040,1002-1108,30); coxae 107 (107,106-118,30) with IB 69
(70,67-75,30); trochanter 83 (84,91-86,30) with IB 71 (72,68-75,30); basifemur 148
(150,143-160,30) with 3B 96-98 posteriorly, 79-84 anteriorly; telofemur 136 (140,132148.30) with 5B 73-94; genu 184 (187,182-193,30) with 8B 75-81 posteriorly, 77-82

49
anteriorly, without a seta,l k 8 (8,6-9,30) at 0.93 (0.94,0.92-0.97,30); tibia
299(295,292-308,30) with 15B 81-82 posteriorly, and 73-84 anteriorly, 2 4> 21 (23,2127.30) and 23 (25,21-28,30) at 0.06 (0.08,0.05-0.12,30) and 0.90 (0.90,0.88-0.92,30);
tarsus 157 (160,155-167,30) with 23-25B 59-69 posteriorly, 12-38 anteriorly, 1 to 17
(18,16-20,30) at 0.75 (0.74,0.71-0.77,30), 1 ill 33 (34,30-35,30) at 0.93 (0.93,0.900.95,30), 1 fp 19 (21,18-24,30) at 0.98 (0.98,0.96-0.99,30).
Leg III (Fig. 23c): 1246 (1275,1208-1360,30); coxae 113 (117,109-123,30) with IB 75
(76,72-78,30); trochanter 77 (77,73-79,30) with IB 73 (73,70-76,30); basifemur 176
(178,175-184,30) with 3B 73-109; telofemur 176 (178,172-180,30) with 5B 110-117
posteriorly, and 104-109 anteriorly; genu 223 (232,210-238,30) with 8B 129-130
posteriorly, and 85-96 anteriorly; tibia 415 (418,409-426,30) with 15B

104-111

posteriorly, 88-100 anteriorly, 1 <t>2l (23,19-26,30) at 0.04 (0.05,0.03-0.08,30); tarsus
182 (184,180-187,30) with 24B 59-69 posteriorly, 10-39 anteriorly, 1 ip 19 (20,1821.30) at 0.98 (0.97,0.96-0.99), no a> and f observed.
Deutonymph:
Idiosoma: color in life brown, ovoid with 2 pairs of eyes set on each side of prodorsum,
anterior eyes 25 (23-26) long by 25 (23-26) wide, posterior eyes 25 (23-26) long by 25
(23-26) wide; anterior setae 54-56 in length, posterior setae 54-61 in length. Ventral
setae 61-79 anteriorly, 61-73 in length posteriorly. Genital valve with 4-6 setae (29-38);
anal valve with 3-5 setae (23-35).
Gnathosoma: anterior end of gnathosoma with fringe. Palpal trochanter 54 (55,52-57,20)
with 8 setae, 5 short ones 48-52 in length, 3 long setae 67-75, palpal femur 178

50
(180,175-185,20) with 19 setae 54-75 in length, palpal genu 92 (94,90-96,20) with 8
setae 48-115; palpal tibia 120 (124,119-130,20) with 3 setroke spines, claw entire and
8 setae 48-54; palpal tarsus 81 (82,79-84,20) with 4B setae 29-42 in length, 4-6 o> 15-17
at 0.71, 0.75, 0.83 and 0.97 (Fig. 24a, b, c, d).
Prodorsal sclerite (Fig. 25):

anterior end with 5-6 long setae 132-150, SM 132

(134,130-138,20), SS 151 (154,148-162,20), AW 73, PW 56, AL 121, PL 52, 6 setae
(67-92) between SM and SS.
Legs: all legs with two types of setae, one type short 38-70, the other type long 55-118.
Leg I: 2032 (2100,1989-2300,20) long, coxal field 316 (335,300-380,20) with 10-12
setae 88-150, trochanter 115 (120,110-136,20) with 8 setae 77-92 dorsally, and 94-121
ventrally; basifemur 252 (262,245-270,20), 20-21 setae 73-104 long; telofemur 439
(443,427-450,20), 33-36 setae 94-104 anteriorly, and 88-92 posteriorly; genu 437
(440,428-460,20), 38-40 setae 84-88 dorsally, and 90-94 ventrally, 1 a 27 (26,25-31,20)
at 0.80 (0.82,0.77-0.84,20); tibia 510 (514,507-522,20), 26-28 setae 71-77 anteriorly,
and 84-88 posteriorly, 7 <f>29 (28,25-30,20) at 0.11 (0.10-0.14,20), 35 (35,33-36,20) at
0.19 (0.17-0.22,20), 33 (33,30-34,20) at 0.27 (0.24-0.30,20), 35 (35,33-36,20) at 0.37
(0.35-0.38,20), 38 (38,36-40,20) at 0.50 (0.47-0.52,20), 40 (42,40-44,20) at 0.71 (0.680.73,20), 38 (38,35-39,20) at 0.78 (0.76-0.80); tarsus 278 (282,268-289,20), with 2
types o f setae, long setae in length of 56-61, the short one 29-48, 3 f setae 56 (56,5258,20) at 0.92 (0.87-0.95,20),77 (78,74-79,20)a t0.96 (0.95-0.98,20), 65 (65,62-67,20)
at 0.98 (0.96-0.99,20), 1-2 famulus 7 each (8,6-9,20) at 0.89 (0.87-0.90,20) and 0.95
(0.94,0.92-0.96,20), 30-32

oj

in 3 rows and 2 types, long one 29-31, short one 12-15.

51

Leg II: 1467 (1500,1300-1621,20) long, coxal field 311 (315,310-325,20) with 9 setae
88-102 anteriorly, and 54-69 posteriorly; trochanter 157 (160,155-168,20) with 10 setae
75-84 anteriorly, 75-84 posteriorly; basifemur 150 (152,147-158,20), 13-15 setae 65-79;
telofemur 284 (290,250-330,20), 28-31 setae 75-77 anteriorly, 65-81 posteriorly; genu
182 (186,178-190,20), 26-32 setae 99-103 anteriorly, and 63-75 posteriorly, 1 a 21
(21,19-24,20) at 0.06 (0.07,0.05-0.08,20) and 1 k 7 (7,6-9,20) at 0.90 (0.89,0.870.93,20); tibia 484 (488,476-510,20) with 43-45B setae 77-88 anteriorly, 75-79
posteriorly, 2 <j> 23 (24,22-26,20) at 0.04 (0.03-0.04,20), 27 (28,25-29,20) at 0.07
(0.06,0.04-0.09,20); tarsus 203 (207,200-212,20),two types o f setae: barbed setae 81-83
anteriorly, 77-88 posteriorly, featherlike setae 35-44 anteriorly, and 48-61 posteriorly,
6 o) in two forms: 3 long and acute 15-22 at 0.46-0.65, 3 short and round

12-13 each

at 0.57,0.65 and 0.67, 5 f 71 (71,70-72,20) at 0.80, 71 (70,69-73,20) at 0.79 (0.780.82,20), 81 (81,79-83,20) at 0.93 (0.92,0.90-0.95,20), 40 (41,40-42,20) at 0.96
(0.96,0.94-0.97,20), 48 (48,46-50,20) at 0.98 (0.97,0.96-0.99,20).
Leg III: 1827 (1842,1790-1880,20) long, coxal field 289 (290,278-320,20), 6 setae 54-86
anteriorly, 59-94 posteriorly; trochanter 148 (150,146-164,20), 6-8 setae 88-94
anteriorly, 36-54 posteriorly; basifemur 240 (247,238-255,20), 13-14 setae 46-63 in
length; telofemur 359 (360,340-375,20), 28-32 setae 74-77 anteriorly, 79-81 posteriorly;
genu 330 (330,314-340,20), 29-32 setae 99-104 anteriorly, and 75-92 posteriorly, 1 a 23
(22,20-25,20)at 0.05 (0.06,0.05-0.08,20); tib ia525 (534,510-550,20), 44-46 setae 73-94
anteriorly, 67-90 posteriorly, 2 0 23 (23,20-25,20) at 0.03 (0.03,0.03-0.04,20), 29
(29,26-33,20) at 0.07 (0.068,0.060-0.072,20), 1 k 8 (7,5-9,20) at 0.89 (0.91,0.88-

52
0.94,20); tarsus 225 (230,218-243,20), barbed setae 31-75 anteriorly, 75-82 posteriorly,
featherlike setae 31-56 anteriorly, 27-42 posteriorly, 2

cj

13 (15,12-17,20) at 0.63

(0.64,0.60-0.66,20), 12 (12,11-14,2 0 )at0.74 (0.75,0.73-0.76,20),5 f: 71 (71,70-73,20)
at 0.78 (0.77,0.75-0.80,20), 69 (69,67-70,20) at 0.84 (0.82,0.79-0.86,20), 84 (85,8286,20) at 0.93 (0.93,0.90-0.95,20), 2 f 47-49 in length at 0.96 and 0.97 respectively,
1 famulus 7 (7,5-9,20) at 0.86-0.89.
Leg IV: 2982 (2975,2856-3210,20), coxal field 315 (320,290-320,20), 7 setae 48-59
anteriorly, 63-77 posteriorly; trochanter 143 (142,138-146,20), 6 setae 86-90 anteriorly,
44-61 posteriorly, basifemur 273 (270,265-284,20), 22-25 setae 82-98 anteriorly, 59-73
posteriorly, telofemur 689 (690,658-705,20), 43-45 setae 100-105 anteriorly, 84-94
posteriorly; genu 585 (590,560-610,20), 32-34 setae 98-107 anteriorly, 81-94 posteriorly,
1 a 21 (23,19-25,20) at 0.07-0.09; tibia 1003 (1020,987-1030,20), 80-82 setae 92-111
anteriorly, 100-109 posteriorly, 3 0 29 (29,26-31,20) at 0.02 (0.01-0.03,20), and 27
(25,23-29,20) at 0.03 (0.03,0.03-0.05,20), 25 (23,22-27,20) at 0.04 (0.04,0.03-0.07,20);
tarsus 290 (290,282-300,20), barbed setae 65-69 anteriorly, 31-75 posteriorly, featherlike
setae 42-50 anteriorly, 69-73 posteriorly, 2 f 81 (81,78-84,20) at 0.90 (0.89,0.880.93,20), 82 (84,79-85,20) at 0.96 (0.95,0.93-0.97,20), without a>.
Adult female:
Color: in life brown. Idiosoma 2162 (2534,2100-3150,10) long by 1606 (1600,14001948,10) wide. One pair of eyes AW 59 (60,57-64,10), AL 35 (36,33-37,10), PW 54
(53,51-56,10), PL 38 (40,37-43,10). Dorsal setae 2 types, long setae 69-84, short setae
29-46.

53
Prodorsal sclerite (Fig. 26): SS 161 (167,158-170,10); AM 125 (126,117-130,10); AL
167 (170,162-170,10); PL 86 (88,84-90,10); AW 100 (101,96-107,10); PW 77 (78,7480,10); L 608 (614,602-622,10); SBa21 (23,20-25,10); SBp 12 (13,10-15,10). Anterior
area with 13 long setae 123-165, area between AM and SS with 22 setae 129-144.
Ventral short setae 40-73 and long setae 113-188 anteriorly, 42-109 posteriorly.
Genital valves with 64-67 setae 54-69; anal valves with 22-25 setae 44-42.
Gnathosoma (Fig. 27): palpal trochanter 86 (88,83-90,10) with 11 setae 59-117; palpal
femur 249 (250,237-253,10) with 38-42 setae 44-81; palpal genu 167 (168,162-170,10)
with 23-25 setae 61-67 ventrally, 107-125 dorsally; palpal tibia 178 (180,174-188,10)
with 12-14 setae 48-50 anteriorly,and 61-79 posteriorly, tibia claw entire with 5 teeth;
palpal tarsus 129 (130,125-137,10), 20 setae 62-64 anteriorly, 46-56 posteriorly, 10-11
w 17-25 in length, 9-10 f a t 0.42-0.95.
Leg I:

2151 (2460,2100-2846,5) long from trochanter to tarsus, coxal field 401

(456,400-480,5), anterior setae 121-161 in length, posterior setae from 129 to 146;
trochanter 205 (238,200-264,5), 135-144 anteriorly, 65-77 posteriorly; basifemur 355
(354,328-369,5), 54-86anteriorly, and 67-69 posteriorly; telofemur 407 (455,400-518,5),
56-63 anteriorly, 69-73 posteiorly, with 6 nude setae 46-69 long at 0.35-0.96; genu 573
(523,475-592,5), 100-105 anteriorly and 54-71 posteriorly, 10 nude setae: 1 in length of
63 (60,58-65,5) at 0.18 (0.17,0.16-0.19,5), 3 N 52 (52,48-53,5) at 0.50 (0.50,0.480.52,5), 44 (42,40-45,5) at 0.59 (0.57,0.56-0.60,5), 88 (86,84-89,5) at 0.65 (0.64,0.620.66,5), 3 N at anterior area 46 (46,44-47,5) at 0.77 (0.75,0.74-0.78,5), 79 (77,75-79,5)
at 0.82 (0.84,0.80-0.85,5), 38 (38,35-39,5)at 0.84 (0.84,0.82-0.85,5), 3 N at front edge

54

Figs. 20-24. Erythraeus michiganensis n, sp. (Larva and deutonymph):
20a-b. dorsal and ventral idiosoma (larva);
20c-d. dorsal, ventral setae and eyes (larva);
23a-c. leg I-III genu-tarsus (larva);
24a. palpals (deutonymph);
24b. palpal genu, tibia and tarsus (deutonymph);
24c. palpal tibia (deutonymph);
24d. palpal tarsus (deutonymph).
Scale lines for Figs. 20a-b, 23a-c, 24a each represent 100 ^m ; scale lines for Figs. 20cd, 21, 24b, c, d each represent 50 ftm.

56

Fig. 22a-d. Erythraeus michiganensis n. sp. (larva):
22a-b. dorsal and ventral view of gnathosoma;
22c-d. pal pals, palpal tibia and palpal tarsus.
Scale line for Fig. 22a-b represents 100 /im; scale lines for Fig. 22c-d represent 50 fim.

Figs. 25-26. Erythraeus michiganensis n. sp. (deutonymph and female): prodorsal
sclerite. Scale line represents 100 /*m.

Fig. 27-28. Erythraeus septemsetalis n. sp. (female):
27. palpals;
28. prodorsal sclerite.
Scale line for Fig. 27 represents 50 /tm; scale line for Fig. 28 represents 100 pm.

57

58
88 (86,85-90,5) at 0.91 (0.90,0.88-0.92,5), 44 (42,40-44,5) at 0.93 (0.93,0.92-0.94,5),
88 (88,86-90,5) at 0.95 (0.95,0.94-0.97,5), 2 a 21-25 at 0.02-0.04, 1 k 12 (12,10-13,5)
at 0.93 (0.92,0.90-0.94,5); tibia 618 (645,600-736,5), 63-69 anteriorly, 50-52
posteriorly, 14-16 <f>: 5 <f>at basal 25 (25,23-27,5) at 0.24 (0.24,0.22-0.25,5), 29 (28,2629.5) at 0.25 (0.25,0.24-0.26,5), 24 (24,22-26,5) at 0.25 (0.25,0.23-0.26,5), 29 (28,2629.5) at 0.34 (0.34,0.32-0.35,5), 25 (25,24-27,5) at 0.45 (0.45,0.44-0.46,5), 5 0 at
middle 31 (30,28-32,5) at 0.51 (0.50,0.49-0.52,5), 29 (28,26-29,5) at 0.58 (0.58,0.570.59,5), 25 (24,23-25,5) at 0.63 (0.62,0.60-0.64,5), 29 (29,27-32,5) at 0.72 (0.72,0.700.73,5), 27 (26,25-29,5) at 0.74 (0.73,0.72-0.75,5), 5 0 at front 33 (34,32-35,5) at 0.83
(0.84,0.82-0.85,5), 27 (27,27-32,5) at 0.93 (0.93,0.92-0.94,5), 27 (26,24-29,5) at 0.96
(0.96,0.94-0.98,5), 29 (27,26-31,5) at 0.96 (0.96,0.95-0.97,5), 29 (28,26-29,5) at 0.98
(0.98,0.95-0.99,5), 1 k 12 (11,10-13,5)at 0.88 (0.87,0.85-0.89,5); tarsus 487 (480,470490.5), 40-48 anteriorly, 48-52 posteriorly, 43-46 long oi 23-29 at 0.28-0.92, 19-20 short
w 11-13 at 0.48-0.94, 3 i t 56 (56,54-57,5) at 0.98 (0.97,0.96-0.97,5), 71 (72,70-74,5)
at 0.99 (0.99,0.99-0.996,5), 27 (27,25-28,5) at 0.99 (0.99,0.99-0.995,5), 3 ip 44
(44,42-45.5) at 0.99 (0.99,0.98-0.99,5), 54 (54,52-55,5) at 0.98 (0.97,0.96-0.99,5), 31
(31,30-33,5) at 0.99 (0.99,0.99-0.995,5).
Leg II: 2192 (2340,2006-2680,5), coxal field 481 (450,425-490,5), 88-171 anteriorly,
and 88-144 posteriorly; trochanter 256 (234,216-268,5), 77-111 anteriorly, and 77-78
posteriorly; basifemur 203 (235,200-260,5), 65-69 anteriorly, 54-58 posteriorly;
telofemur 384 (398,378-414,5), 56-63 anteriorly, 56-58 posteriorly, with 4 N 53 (54,5255.5) at 0.64 (0.64,0.62-0.66,5), 52 (52,50-54,5) at 0.66 (0.66,0.64-0.67,5), 61 (62,60-

59
63.5) at 0.89 (0.89,0.86-0.90,5), 48 (48,46-49,5) at 0.98 (0.98,0.96-0.99,5); genu 424
(420,413-430,5), 84-102 anteriorly, 46-61 posteriorly, 4 N 38 (37,36-39,5) at 0.46
(0.45,0.44-0.47,5), 54 (54,52-55,5) at 0.77 (0.77,0.75-0.78,5), 69 (69,68-70,5) at 0.77
(0.77,0.76-0.79,5), 69 (69,68-70,5) at 0.90 (0.90,0.89-0.92,5), 2 a 31 (31,29-33,5) at
0.12 (0.12,0.11-0.13,5), 27 (27,25-28,5) at 0.26 (0.26,0.25-0.27,5); tibia 560 (580,550605.5), 71-77 anteriorly, 52-58 posteriorly, 2 huge setae 92-111 at 0.57-0.67, 4 huge
setae at anterior edge in length from 96 to 115, 10-11 <t>25-33 at 0.02-0.69; tarsus 365
(370,358-374,5), anterior setae 50-63 in length, 48-58 posteriorly, 12-13 to 23-29 at
0.54-0.93, 3 fh 59-67 at 0.91-0.97, 2 fp 59 (59,58-59,5) at 0.94 (0.95,0.94-0.97,5), 63
(64,62-65,5) at 0.98 (0.98,0.97-0.99,5), 9 f a t ventral 50-52 at 0.53-0.98 region.
Leg III:

2650 (2550,2348-2780,5), coxal field 432 (410,393-450,5), 61-109

anteriorly,and 104-171 posteriorly, trochanter 223 (210,200-230,5), setae length from 77
to 111, basifemur 353 (300,198-360,5), anterior setae 56-65, posterior setae 54-58,
telofemur 468 (466,450-480,5), 61-69 anteriorly, and 58-61 posteriorly, 3 N 54 (54,5356.5) at 0.42 (0.42,0.40-0.43,5), 34 (35,33-36,5) at 0.60 (0.60,0.59-0.63,5), 58 (57,5558.5) at 0.90 (0.89-0.93,5); genu 456 (460,445-471,5), anterior setae 69-71, 52-59
posteriorly, with 2 a 20 (21,19-23,5) at 0.03 (0.03,0.01-0.04,5), 25 (25,22-7,5) at 0.06
(0.06,0.04-0.08,5); tibia 752 (745,738-762,5), 61-77 anteriorly, 50-69 posteriorly, 4-5
<t> 28 (28,26-29,5) at 0.02 (0.02,0.01-0.03,5), 28 (28,27-29,5) at 0.03 (0.03,0.020.05,5), 26 (25,23-26,5) at 0.09 (0.08,0.07-0.09,5), 21 (21,20-23,5) at 0.10 (0.09,0.090.12,5), 2 huge setae at midventral region 0.57-0.72, 107 and 133 in length; tarsus 399
(400,385-420,5), anterior setae 59-71, posterior setae 52-63, 3 fh 73 (73,70-74,5) at 0.90

60
(0.90,0.88-0.92,5), 77 (77,75-78,5) at 0.92 (0.92,0.90-0.94,5), 90 (91,89-93,5) at 0.95
(0.95,0.93-0.96,5), 2 ft) 63 (63,61-65,5) at 0.96 (0.96,0.05-0.97,5), 59 (59,52-55,5) at
0.97 (0.95-0.98,5), 59 (59,57-60,5) at 0.98 (0.98,0.96-0.99,5), 3 u at middle to anterior
reagion, 35-40 in length at 0.57-0.75.
Leg IV: 3610 (3200,3056-3760,5), coxal field 579 (480,437-584,5), anterior setae 5577, posterior setae 90-130; trochanter 240 (215,191-254,5), anterior setae 44-46,
posterior setae 65-90; basifemur 380 (338,279-385,5), 63-67 anteriorly, and 38-44
posteriorly; telofemur 452 (412,397-463,5), 67-84 anteriorly, 56-61 posteriorly, 4 N 40
(41,40-43,5) at 0.40 (0.40,0.38-0.44,5), 50 (49,46-50,5) at 0.65 (0.64,0.63-0.66,5), 81
(81,80-83,5) at 0.95 (0.95,0.93-0.96,5), 73 (73,70-74,5) at 0.96 (0.95,0.94-0.97,5);
genu 425 (420,418-430,5), anterior setae 63-71, posterior setae 52-54, 3 N 48 (48,4549.5) at 0.68 (0.67,0.65-0.70,5), 90 (90,89-93,5) at 0.95 (0.95,0.93-0.96,5), 90 (90,8892.5) at 0.96 (0.96,0.95-0.97,5), 2 a 23 (23,22-24,5) at 0.042 (0.04,0.03-0.05,5), 25
(25,22-25,5) at 0.026 (0.03,0.02-0.04,5); tibia 1335 (1335,1320-1358,5), anterior setae
65-92, posterior setae 54-56, 4 N 40 (40,38-43,5) at 0.16 (0.15,0.14-0.17,5), 46 (46,4447.5) at 0.46 (0.45,0.43-0.46,5), 48 (46,43-48,5) at 0.54 (0.53,0.52-0.55,5), 52 (52,5052.5) at 0.75 (0.75,0.73-0.76,5), 3 <t>25-31 at 0.02-0.07, 6 huge setae range from 150
(150,147-153,5) to 182 (178,176-184,5), 3 at anterior end (0.82-0.96), 3 at midventral
0.52-0.68; tarsus 539 (525,510-543,5), 59-61 anteriorly, 48-59 posteriorly, 1 fti 88
(88,85-89,5) at 0.96 (0.95,0.94-0.97,5), 3 dorsal f a t 0.52-0.90, 68-86 in length, 9 f a t
ventral region 0.43-0.87, 35-63 in length, no u observed.

61
Adult Male:
Color: in life brown. Idiosoma ovoid, 1813 (1920,1750-2100,5) long by 1396
(1450,1260-1605,5) wide. Two pairs of eyes set on an ocular sclerite, 111 (112,110116.5) long and 71 (72,70-73,5) wide, AW 33 (33,31-34,5), AL 36 (36,34-37,5), PW
40 (41,40-43,5), PL 40 (41,39-42,5).
Ventral setae of two distinct types: long and truncate 109-123, and short and
pointed setae 25-54; majority of setae short. Anal valves with two types of setae: long
setae 123-137, short setae 54-61. Genital valves with 89-94 setae 61-69 in length.
Prodorsal sclerite: SS 163 (165,156-172,5); AM 122 (125,116-130.5); SBa 21 (21,1922.5); SBp 19 (19,17-20,5); AL 125 (125,119-128,5); PL 96 (96,93-97,5); ISD 437
(440,435-448,5); L 577 (578,565-585,5); ASBa 79 (79,75-82,5), 10 long setae at anterior
region, 117-159 in length, two types of setae 20-21 at area between SS and SM are short
59-86 and long one 104-129.
Gnathosoma: anterior end with fringe, palpal trochanter 48 (48,45-49,5) with 7-9 setae
61-71; palpal femur 359 (355,347-365,5) with 30-32 setae 73-94; palpal genu 150
(152,144-158,5) with 27-29 setae 61-92; palpal tibia 148 (151,146-156,5), and 5
ventrally projecting spines 19-23 in length, 19-20 setae 40-50, tibia claw entire 52
(52,50-53,5); palpal tarsus 132 (134,129-138,5), 21-23 setae 52-58, 9-10 u setae 15-21
in length at 0.55-0.96, 11-12 f a t 0.49-0.98.
Leg I: 2848 (2670,2430-3100,5), coxal field 462 (432,378-470,5), anterior setae 121236, posterior setae 82-159; trochanter 213 (210,189-235,5), 44-117 anteriorly, 42-96
posteriorly; basifemur 361 (358,347-370,5), 69-79 anteriorly, 58-79 posteriorly, 1 N 42

62
(42,39-44,5) at 0.65 (0.65,0.63-0.66,5); telofemur 541 (534,498-560,5), anterior setae
71-86, posterior setae 65-75, 7 N 44 (44,42-46,5) at 0.40 (0.41,0.39-0.43,5), 42 (42,4044.5) at 0.46 (0.45,0.43-0.47,5), 52 (52,51-54,5) at 0.57 (0.56,0.54-0.58,5), 56 (56,5457.5) at 0.57 (0.57,0.55-0.58,5), 73 (73,71-74,5) at 0.65 (0.64,0.62-0.66,5), 73 (73,7174.5) at 0.71 (0.72,0.70-0.73,5), 84 (85,82-86,5) at 0.89 (0.88,0.85-0.90,5); genu 600
(598,550-614,5), anterior setae 77-102, posterior setae 59-73, 13 N 38-98 in length at
0.28-0.98 region, 2 a 29-35 at 0.11-0.49; tibia 641 (625,548-688,5), 69-77 anteriorly,
65-84 posteiorly, 8 N: 2 N posterioly 17-38 in length at 0.21-0.34, 3 N at middle, 44-48
at 0.55-0.64, 2 N at anterior region 0.78-0.79, 59-63 in length, 1 N at anterior end 0.92
(0.92,0.90-0.95,5), 73 (73,71-74,5), 5 0 at posterior region from 0.04-0.15 25-31, 1 0
at 0.23 (0.24,0.21-0.25,5) 17 (16,15-18,5); tarsus 493 (452,380-498,5), 61-67 anteriorly,
44-56 posteriorly, 4 f 54-92 at 0.87-0.98, 92-97 w 58-61 at 0.23-0.96, 4 f a t 0.92-0.97,
2 fp at 0.96-0.98.
Leg II: 2310 (2450,2130-2780,5), coxal field 489 (477,451-520,5), anterior setae 115223, and posterior setae 100-163; trochanter 221 (223,219-242,5), 50-115 anteriorly, and
46-58 posteriorly; basifemur 292 (282,271-298,5), 59-73 anteriorly, 61-71 posteriorly,
with 1 N 42 (41,40-44,5)at 0.65 (0.64,0.62-0.66,5); telofemur 412 (396,368-432,5), 6592 anteriorly, 59-63 posteriorly, with 5 N: 2 at 0.25-0.28, 44-46, 1 at 0.40 (0.42,0.400.45,5) in length o f 44 (44,42-46,5), 1 at 0.78 (0.77,0.75-0.78,5) 61 (62,60-64,5), 1 at
0.93 (0.93,0.92-0.94,5); genu 456 (455,430-478,5), 71-73 anteriorly, 54-58 posteriorly,
3 N 38 (38,35-39,5) at 0.51 (0.50,0.49-0.53,5), 65 (65,63-66,5) at 0.80 (0.80,0.780.82,5), 67 (66,64-69,5) at 0.91 (0.90,0.88-0.93,5), 2 a at rear region from 0.08 to

63
0.20, 21-27, 4 huge setae at anterior region from 0.86 to 0.97, 90-125; tibia 552
(534,520-566,5), 9-10 N: 2 at 0.23-0.36, 38 each, 4 at middle 0.52-0.62, 44-48, 2 at
anterior region 0.76-0.86, 52-71, 1 at anterior end 0.93 (0.93,0.92-0.95,5), 86 (85,8386.5), 6 <t>at rear region 0.05-0.16, 25-27, 2 huge setae at 0.34 and 0.35, 96-111, 2 at
middle 0.52-0.60, 96-121, 1 at 0.78 (0.77,0.75-0.79,5), 113 (114,110-120,5), 2 at
anterior end 0.94-0.95 , 94-115; tarsus 376 (360,349-410,5), 61-73 anteriorly, 44-63
posteriorly, 2 f a t 0.85-0.97, 54-94 in length, 3 w at anterior end 0.91-0.98, 46-54, 6
w at ventral 0.44-0.86, 46-52 in length.
Leg III: 2593 (2285,2187-2890,5), coxal field 539 (528,478-550,5), 90-117 anteriorly,
and 71-180 posteriorly; trochanter 280 (266,257-297,5), 92-105 anteriorly, and 46-56
posteriorly; basifemur 198 (188,173-253,5), 61-73 anteriorly, 50-52 posteriorly, with 1
N 50 (48,46-52,5) at 0.91 (0.91,0.89-0.93,5); telofemur 493 (454,427-534,5), 59-82
anteriorly, 61-67 posteriorly, 3 N 44 (43,40-46,5) at 0.54 (0.53,0.52-0.56,5), 82 (83,8085.5) at 0.92 (0.92,0.91-0.93,5), 86 (87,84-88,5) at 0.94 (0.94,0.92-0.95,5); genu 474
(475,470-480,5), 63-86 anteriorly, 42-58 posteriorly, 5 N 42 (43,38-44,5) at 0.37
(0.35,0.32-0.38,5),58 (58,55-59,5) at 0.80 (0.78,0.76-0.82,5), 104 (102,98-105,5) at
0.93 (0.93,0.90-0.95,5), 96 (96,93-97,5) at 0.94 (0.93,0.91-0.96,5), 100 (99,98-105,5)
at 0.95 (0.96,0.94-0.97,5), 1 a 21 (21,18-23,5) at rear 0.06-0.08; tibia 775 (750,725780.5), 10 N: 1 at rear region 0.28 (0.27,0.24-0.30,5), 42 (42,41-43,5) in length, 1 at
middle 0.51 (0.50,0.48-0.53,5) 40 (40,38-42,5), 6 at anterior region: 56 (55,53-56,5)
at 0.72 (0.72,0.69-0.74,5), 59 (59,56-62,5) at 0.75 (0.74,0.72-0.76,5), 59 (59,57-60,5)
at 0.79 (0.79,0.78-0.82,5), 58 (57,56-58,5) at 0.82 (0.83,0.80-0.85,5), 69 (70,68-73,5)

64
at 0.88 (0.88,0.86-0.89,5), 56 (56,53-58,5) at 0.89 (0.89,0.86-0.90,5), 90 (90,88-93,5)
at 0.97 (0.97,0.95-0.98,5), 86 (85,84-87,5) at 0.98 (0.98,0.96-0.99,5), 5 huge setae at
anterior region from 0.88 to 0.93, 92-132 in length, 4-5 <t>at rear region 0.03-0.06, 2131, 1 <t>at 0.90 (0.92,0.89-0.93,5), 25 (25,23-26,5); tarsus 401 (388,357-412,5), 59-73
anteriorly, 50-56 posteriorly, 3 {*73 (73,72-75,5) at 0.92 (0.92,0.91-0.94,5), 75 (75,7276.5) at 0.93 (0.94,0.92-0.95,5), 81 (81,79-82,5) at 0.97 (0.96,0.94-0.98,5), 2 to 12-17
at 0.49-0.74.
Leg IV: 4078 (3658,3220-4358,5), coxal field 591 (520,479-624,5), 71-90 anteriorly, 50198 posteriorly; trochanter 295 (264,236-312,5), 61-88 anteriorly, 25-46 posteriorly;
basifemur 384 (355,327-398,5), 65-67 anteriorly, 54-61 posteriorly, with 1 N 50 (49,4650.5) at 0.94 (0.93,0.92-0.95,5); telofemur 704 (679,624-715,5), 71-77 anteriorly, 56-73
posteriorly, 3 N 44 (44,42-46,5) at 0.70 (0.70,0.67-0.72,5), 84 (84,81-85,5) at 0.95
(0.95,0.92-0.96,5), 86 (86,83-88,5) at 0.96 (0.96,0.93-0.98,5); genu 775 (745,713783.5), 71-86 anteriorly, 67-71 posteriorly, 6 N 42 (42,40-44,5) at 0.58 (0.56,0.540.59,5), 44 (44,42-47,5) at 0.74 (0.74,0.72-0.76,5), 58 (57,55-58,5) at 0.87 (0.86,0.850.88,5), 100 (97,95-99,5) at 0.95 (0.95,0.93-0.96,5), 98 (98,96-99,5) at 0.96 (0.96,0.940.97,5), 102 (98,96-104,5) at 0.96 (0.95,0.94-0.97,5), 3 cr at 0.03-0.05, 25-29; tibia
1408 (1320,1109-1523,5), 11-12 N at 0.20-0.93,42-71, 4 </>at 0.02-0.04, 23-31, 5 huge
setae 146-188 at 0.42-0.96; tarsus 512 (508,486-526,5), 65-73 anteriorly, 56-59
posteriorly, 2 {It 88-86 at 0.98, 1 dorsal {*52-59 at 0.87-0.89, no o> observed.
Etymology:
The name was derived from the state of Michigan.

65
D istribution o f Types:
The holotype, 20 larval, 10 deutonymphal, and 5 adult female paratypes are in
Department o f Zoology, Michigan State University, East Lansing, MI. One larval,
deutonymphal and adult female paratype will be deposited in each of the following
institutions: National Museum of Natural History, Washington, DC; British Museum
(Natural History), London, U. K.; Department of Biology, Fudan University, Shanghai,
PRC.

Erythraeus septemsetalis n. sp.
Type series:
The description is based on the morphology of five adults collected on 21 July,
1984 from a cedar bog near Sagola, Michigan; no larvae and nymphs are available.
D escription:
A dult female:
Idiosoma: color in life dark brown. Idiosoma 2714 (2800,2478-3210,5) long by 2574
(2448,2168-2774,5) wide. Dorsal setae in two types, short and stout setae 36-38 long,
long setae 71-81; ventral setae thin and smooth, 58-71 in length for short setae, 86-92
in length for long setae.
Palpals: palpal femur 209 (210,197-220,5); palpal genu 237 (223,216-257,5); palpal tibia
1781 (173,168-178,5), palpal tibia claw entire 50 (50,47-53,5) long with 5 spines at inner
edge; palpal tarsus 132 (135,128-143,5).
Prodorsal sclerite (Fig. 281: SS 150 (148,144-152,5); SM 196 (197,188-202,5); AW 142

66
(143,139-145,5);

PW 77 (77,73-78,5); 712 (708,703-721,5) long with 15 long setae at

the front of the sclerite 71-123 in length.
Leg I: 3599 (3650,3267-3878,5), coxal field 537 (524,517-546,5); trochanter 236
(238,212-247,5); basifemur 435 (428,414-448,5), with 2 N 40-92 at 0.65-0.87; telofemur
620 (612,608-635,5) with 5 N 42-71 at 0.62-0.92; genu 852 (843,827-866,5) with 11-12
N 55-82 at 0.18-0.96, 2 a 24-31 at 0.46-0.81; tibia 867 (870,855-897,5) with 10-12 0
23-30 at 0.26-0.81, 24-26 N 46-70 at 0.16-0.92; tarsus 589 (590,575-611,5) with 157162 a) 25-44 at 0.57-0.98, 12-13 f 56-79 at 0.82-0.98, 2 Jp 89-95 at 0.97-0.99.
Leg II:

2775 (2803,2576-2897,5), coxal field 591 (585,577-598,5); trochanter 280

(286,277-295,5); basifemur 330 (328,307-333,5) with 2 N 46-88 at 0.64-0.87; telofemur
510 (505,487-532,5) with 4 N 42-59 at 0.34-0.88; genu 570 (557,534-588,5) with 2 a
23-33 at 0.04-0.06, 8-9 N 33-44 at 0.40-0.93; tibia 717 (708,695-723,5) with 4-5 4>2435 at 0.02-0.28, 12-14 N 34-59 at 0.12-0.94; tarsus 368 (358,313-377,5) with 17-19 w
13-21 at 0.55-0.87, 5-6 dorsal f 42-69 at 0.71-0.92, 2 fh 71-77 at 0.95-0.98, 2 f 52-57
at 0.96-0.98.
Leg III:

3420 (3277,3184-3579,5), coxal field 543 (540,527-563,5); trochanter 253

(244,218-267,5); basifemur 378 (358,343-388,5) with 3 N 50-88 at 0.62-0.83; telofemur
627 (616,608-647,5) with 2-3 N 38-52 at 0.30-0.57; genu 719 (707,678-732,5) with 3
o 7-13 at 0.02-0.05, 6-7 N 31-42 at 0.60-0.97; tibia 1032 (1020,988-1137,5) with 3-4
4>23-26 at 0.0.01-0.10,9-10 N 35-58 at 0.43-0.97; tarsus 410 (408,388-422,5) with 8-9
w 10-15 at 0.33-0.74,5 dorsal f 42-48 at 0.71-0.95, 1 (li 72-77 at 0.96-0.98, 3 fp 48-58
at 0.96-0.98.

67
Leg IV:

5645 (5270,5108-5630,5), coxal field 735 (727,705-764,5); trochanter 280

(276,266-292,5); basifemur 702 (696,688-710,5) with 1 N 42-44 at 0.81-0.86; telofemur
1045 (1033,1012-1103,5) with 6-7 N 33-67 at 0.21-0.97; genu 1174 (1109,1078-1205,5)
with 2 a 21-25 at 0.02-0.03, 3-4 N 38-42 at 0.44-0.97; tibia 1868 (1815,1786-1903,5)
with 3-4 <t>24-29 at 0.02-0.04, 14-15 N 38-69 at 0.31-0.91; tarsus 575 (571,522-590,5)
without w, 2 fh 77-84 at 0.92-0.95, 2 ip 52-71 at 0.96-0.98, 3 dorsal f 48-52 at 0.450.74.
Etymology:
The species name was derived from the sclerite of the adults, which has seven
long setae on its anterior edge, distinguishing the species from others.
Discussion:
The genus was erected by Latreille in 1806 with the type species Acarus
phalangoides de Geer,

1778.

Southcott (1946) created the monotypic genus

Parerythraeus, basing it on the type species Parerythraeus gregoryi Southcott, 1946. In
further work (1961), he included

Parerythraeus tragardhi = Erythraeus dugesi

Tragardh, 1904 in the genus. About nine species were described from Europe and at least
5 species from the United States (Beron, 1982,1988; Haitlinger,1987; Southcott, 1961;
Turk, 1981).
Erythraeus septemsetalis differs from E. michiganensis in having larger AW
(141:99), longer ASE (149:124), PSE (195:161), longer prodorsal sclerite (711:607) and
longer legs (3598:2158,2775:2191,3419:2549,4470:3607). However, the most important
characters which seperate the two species is the location of sclerite setae; in the former,

68
these setae are located on the prodorsal sclerite, in the latter, they are on the dorsal
idiosoma.
Distribution o f Types:
The holotype, 5 female paratypes are in Department o f Zoology, Michigan State
University, East Lansing, MI.

Subfamily Callidosomatinae:
Abrotophus welboumi n. sp.
Type series:
Holotype: 1 larva collected on April 30, 1991 from a nymph of a leafhopper.
Additional 30 paratypes collected from May 4-21, 1991 in the same location. Fifteen
paratype deutonymphs reared from larvae in the laboratory. Five paratype adults
collected in the field in July, 1991.
Larval description:
Color: in life yellow. Idiosoma ovoid 583 (592,544-612,30) long, 279 (269,255-297,30)
wide; one pair o f eyes on each side of prodorsum 17 (17,16-18,30), distance between
eyes 82 (85,80-87,30). Dorsum hypertrichous with 57 (55,51-58,30) setae, 38 (38,3539,30) anteriorly, 52 (52,50-55,30) posteriorly (Fig. 29a).
Ventral idiosoma with one pair (la) of intercoxal setae between coxal field leg I,
46 (44, 42-47,30), one pair (lb ) 50 (48,47-51,30) at coxal field I; one pair (2a) of
intercoxal setae between coxal field leg II, 38 (34,32-38,30), One pair (2b) 38 (35,32-38,
30) at coxal field II; one pair o f intercoxal setae (3a) 42 (43,42-46,30), one pair (3b) 44

69
(45,41-47,30) on coxal field III. Four setae located between coxal field II and III 28, 32,
34 and 16 respectively; after coxal field III 18 dorsal setae 29-46 (Fig. 29b).
Prodorsal sclerite (Fig. 30): anterior margin concave with lateral shoulders, widest at
level of PL setae; two pairs of sensory setae trichobothrial, second pair near posterior
margin.

SS 44 (42, 38-47,30); AL 69 (63,52-70,30); PL 63 (59,55-67,30); AW 59

(56,54-60,30); MW 74 (72,69-77,30); PW 78 (74,72-80,30); SM 68 (63,57-71,30);
ASBa 17 (16,15-18,30); ISD 40 (38,37-43,30); LX 9 (9,7-10,30); A 53 (49,46-56,30);
AAS 17 (15,14-19,30); L 84 (80,78-88,30).
Gnathosoma (Fig. 31): palpal seta! formula fPp=0-BB-BBB-6N-3N2Bco; palpal genu
with 1 "knob"; palpal tibial claw entire 21 (22,18-25,30) with 1 small clawlike seta and
5 nude setae; palpal tarsus with 1 long seta 67 (62,58-68,30), 1 comblike seta 42 (42,3844,30), one small leaflike seta 7 (8,6-9,30), 1

and 2 nude setae.

Leg I (Fig. 32a): 270 (286,266-348,30) long; coxal field with 1 branched seta (IB) 50
long (48,44-53,30); trochante 2B 50 (49,47-54,30), 57 (56,52-59,30); basifemur 4B (4663); telofemur 5B (46-53,30); genu 1IB, 1 cr 21 and 19 at 0.79 (0.80,0.79-0.84,30) and
1 k 4 (4,3-4,30) at 0.93 (0.94,0.88-0.96,30); tibia 13B, 2 0 17 (16,15-20,30) and 23
(23,22-26,30) at 0.83 (0.84,0.80-0.87,30) and 0.89 (0.89,0.87-0.92,30), respectively,
1 k 6 (6,4-8,30) at 0.87 (0.88,0.85-0.90,30); tarsus with 1 u> 19 (20,18-23,30) at 0.77
(0.75,0.72-0.82,30);

1 famulus 4 (4,3-4,30) at 0.85

(0.85,0.81-0.89,30); 1

42

(42,38-44,30) at 0.83 (0.83,0.80-0.85,30), 1 companion seta; 1 £p 17 (16,15-19,30) at

70

Figs. 29-31. Abrolophus welboumi n. sp. (larva):
29a-b. dorsal and ventral idiosoma;
30. prodorsal sclerite;
31a-b. gnathosoma and palpals.
Scale lines for Figs. 29, 31a represent 100 /*m; scale lines for Figs. 30, 31b represent
50 /*m.

71

/
\
A

*
AM /A L

71
T

O

72
0.94 (0.93,0.90-0.98,30).
Leg II (Fig. 32b): 225 (238,217-288,30) in length, coxal field with IB 44 (44,40-46,30);
trochanter with 2B 36-42, basifemur 4B 42-58; telofemur 5B 33-44; genu with 9B 27-35,
1 a 15 (15,12-17,30) at 0.76 (0.74,0.72-0.79,30), 1 k 4 (4,4-7,30) at 0.84 (0.85,0.810.88,30); tibia with 13B 40-46, 2 * 13 (14 and 17 (16,15-19,30) at 0.79 (0.78,0.750.80,30) and 0.74 (0.73,0.70-0.76,30) respectively; tarsus with 23B 29-35; 1 w 11 (11,913.30) at 0.52 (0.53,0.50-0.56,30), 1 f 34 (33,30-35,30) at 0.72 (0.72,0.69-0.74,30),
1 subterminal eupathid and 1 companion seta 4 (4,3-7,30) at 0.76 (0.75,0.73-0.79,30).
Leg III (Fig. 32c): 255 (284,247-322,30) long, coxal field with IB 42 (43,41-47,30);
trochanter with 2B 34-40; basifemur with 4B 36-42; telofemur with 5B 36-42; genu with
9B 38-44, 1 a 17 (17,15-18,30) at 0.86 (0.85,0.83-0.87,30); tibia with 13B 38-46, 1 *
19 (18,16-20,30) at 0.46 (0.46,0.40-0.48,30); tarsus with 18B 30-44, 1 fp 21 (21,1822.30) at 0.96 (0.95,0.94-0.99,30) and 1 subterminal eupathid 3 (3,3-5,30) at 0.94
(0.95,0.93-0.96,30).
Deutonymph:
Color: in life red. Idiosoma 735 (708,677-767,15) long by 609 (588,576-625,15) wide.
Dorsal setae 31-36 in length; ventral setae 40-42. Anal valve with 7-8 setae (Fig. 33).
Eyes 1 + 1, 13 across.
Palpals: palpal femur 77 (77,73-79,15), 5 setae 31-33 long, 1 long seta 73 (72,70-77,15)
in length; palpal genu 48 (48,45-50,15) with 8 setae 27-33; palpal tibia 23 (22,20-25,15)
with 9 setae 13-27 long, palpal tibia claw entire, 12 (11,10-13,15); palpal tarsus 23
(23,21-25,15) with 9 « 10-19, 2 nude setae, 2 f 13-17 (Fig. 34).

73
Dorsal sclerite: 178 (188,164-203,15) long by 46 (43,37-56,15) wide, AM 107 (113,102125.15) long, SS 48 (57,43-67,15) long.
Legs:

Leg I 758 (755,731-778,15), coxal field 94 (95,92-98,15) with 4 setae 31-36;

trochanter 50 (51,48-55,15) with 5 setae; basifemur 115 (113,108-127,15) with 6 setae;
telofemur 130 (132,129-144,15) with 2 9 36-38 at 0.83 and 0,85 respectively; genu 169
(165,157-182,15) with 5 a 27-38 at 0.47-0.86; tibia 165 (166,157-170,15) with 9 4>23-38
at 0.18-0.82, 1 k 6 (5,4-7,15) at 0.93 (0.94,0.92-0.95,15); tarsus 129 (129,117-134,15)
with 8 to 13-19 at 0.61-0.91, 3 $h 35-38 at 0.67-0.95.
Leg II 418 (412,408-425,15), coxal field 98 (99,95-103,15); trochanter 61 (60,5864.15); basifemur 54 (52,50-56,15); telofemur 67 (65,62-70,15) with 1 9 36 (36,3438.15); genu 88 (89,85-92,15) with 2 a 13-33 at 0.72-0.89; tibia 86 (84,80-88,15) with
2 <t> 17-21 at 0.21-0.40; tarsus 61 (67,57-72,15) with 1 fh 33 (32,30-34,15).
Leg III 409 (405,388-432,15), coxal field 79 (79,76-80,15); trochanter 61 (63,6065.15); basifemur 58 (59,54-63,15); telofemur 73 (72,70-77,15) with 1 $ 31 (31,2834.15); genu 104 (110,102-125,15) with 2 a 36-38 at 0.85 and 0.86, 2 p 19-21 at 0.370.70; tibia 119 (116,110-131,15) with 2 <(>21 each at 0.11-0.13; tarsus 61 (63,61-65,15)
with 1 ill 36 (37,34-38,15) at 0.88 (0.87,0.85-0.90).
Leg IV 760 (747,712-820,15), coxal field 115 (108,102-124,15); trochanter 46
(46,44-48,15); basifemur 88 (92,85-95,15); telofemur 155 (167,148-192,15) with 1 9 44
(46,42-48,15) at 0.89 (0.88,0.86-0.92,15); genu 178 (188,165-197,15) with 3 a 15-25
at 0.51-0.88, 2 p 27 each at 0.57-0.76; tibia 219 (223,207-265,15) with 2 4> 38-40 at
0.50 and 0.85; tarsus 73 (73,70-75,15) with 1 iti 42 (42,38-46,15) at 0.86 (0.88,0.85-

74
0.92,15).
Adult female:
Color: in life red. Idiosoma 1471 (1642,1237-1785,15) long by 783 (797,756-810,15).
Dorsal setae 42-50 long, ventral setae 44-50. Eyes 1 + 131 across. Anal valves with
8 setae; genetal valves 297 (304,286-332,15) long by 96 (98,87-103,15) wide with 62-64
setae 33-38 long (Fig. 36).
Palpals: palpal femur 148 (148,142-156,15) with 28-32 setae and 1 long seta; palpal genu
92 (95,88-98,15) with 25-26 setae; palpal tibia 33 (35,30-37,15) with 12 setae, palpal
tibia claw 23 (28,21-36,15); palpal tarsus 58 (58,55-61,15) with 7 <a and 7-9 eupathidia
and 4 nude setae (Fig. 37).
Prodorsal sclerite (Fig. 38): 412 (426,407-446,15) long, AW 119 (121,107-132,15); PW
61 (64,60-72,15); AM 100 (101,95-106,15); SS 129 (132,117-146,15); SBa 29 (29,2532,15); SBp 21 (23,20-25,15); LX 67 (69,63-70,15); ISD 291 (297,255-314,15) and 3
extra setae anterior to AM setae.
Legs: Leg I 1617 (1723,1335-1827,15), coxal field 184 (178,138-192,15); trochanter
86 (87,82-90,15); basifemur 252 (262,244-278,15); telofem ur322 (332,307-354,15) with
2 N 26-29 at 0.36-0.77; genu 353 (363,342-385,15) with 9-10 a 19-26 at 0.05-0.92, 1
k 6-9 at 0.96-0.98; tibia 316 (320,309-332,15) with 10-11 <f> 19-23 at 0.07-0.63, 1 k 6-9
at 0.95-0.97; tarsus 287 (289,254-310,15) with 82-90 w 13-19 at 0.54-0.98, 2-3 dorsal
r 29-31 at 0.73-0.87, 2

32-34 at 0.96-0.98.

Leg II 1023 (1108,1008-1325,15), coxal 215 (223,208-237,15); trochanter 144
(147,138-153,15);basifemur 130(138,122-145,15); telofemur 186 (187,175-197,15) with

75
1 N 25-29 at 0.41-0.44; genu 223 (228,211-242,15) with 7-8 a 19-23 at 0.33-0.86, 1 k
6-9 at 0.92-0.95; tibia 215 (217,207-238,15) with 4-5 4> 15-19 at 0.08-0.89; tarsus 125
(129,118-136,15) with 1 fh 31-33 at 0.94-0.96, 2-3 dorsal f 31-33 at 0.43-0.80, without
to.

Leg III 1157 (1178,1087-1232,15), coxal field 178 (177,155-183,15); trochanter
146(147,133-168,15);basifemur 141 (148,136-154,15); telofemur205 (210,187-223,15)
with 1 N 27-31 at 0.76-0.88; genu 266 (273,218-310,15) with 6-7 o 15-23 at 0.28-0.78;
tibia 275 (288,253-297,15) with 4-5 <t> 19-25 at 0.06-0.94; tarsus 123 (129,110-133,15)
with 1 fh 35-38 at 0.90-0.93, no to observed.
Leg IV 1950 (1986,1908-1997,15), coxal field 285 (278,231-297,15); trochanter
139 (142,127-147,15); basifemur 215 (223,208-233,15); telofemur 430 (431,407-445,15)
with 1-2 N 31-35 at 0.41-0.93; genu 480 (482,455-510,15) with 6-7 a 23-29 at 0.210.80; tibia 520 (525,504-556,15) 5-6 </> 19-25 at 0.03-0.91; tarsus 169 (167,162-178,15)
with 2 fh 40-42 at 0.93-0.96, no to observed.
Adult male:
Color: in life red. Idiosoma 1375 (1427,1180-1566,15) by 949 (937,878-952,15) wide.
Dorsal setae 40-52 in length, ventral setae 36-44, anal valves with 16 setae, genetal
valves with 88-97 setae.
Pal pals: palpal femur 165 (168,157-171,15); palpal genu 98 (95,90-99,15); palpal tibia
35 (35,32-37,15), palpal tibia claw entire 15 (16,14-18,15); palpal tarsus 59 (61,5766,15) with 12 to, 6 f and 2 nude setae.

76

Figs. 32-38. Abrolophus welboumi n. sp. (larva, deutonymph and adult female):
32a-c. leg I-III (larva);
33. anal valves (deutonymph);
34. palpals (deutonymph);
35. prodorsal sclerite (deutonymph);
36. genital and anal valves (female);
37. palpals (female);
38. prodorsal sclerite (female).
Scale lines for Figs. 32-38 represent 100 /zm.

Figs. 39-40. Abrolophus channingensis n. sp. (larva):
39. prodorsal sclerite;
40a-c. leg I-III genu to tarsus.
Scale line for Fig. 39 represents 50 j*m; scale line for Fig. 40a-c represents 100 pm .

78

Prodorsal sclerite: 337 (312,258-341,15)long, SM 84 (86,83-87,15); SS 111 (119,107126,15); AW 111 (115,107-125,15); PW 50(51,47-55,15); SBa 31 (32,28-35,15); SBp
21 (21,19-26,15); LX 73 (74,70-76,15); ISD244 (253,232-265,15); 8 and 7 setae located
at each side of the area between SM and SS.
Legs: Leg I 1460 (1530,1348-1653,15), coxal field 178 (180,166-189,15); trochanter
130 (133,129-142,15); basifemur 186 (185,173-198,15); telofemur 302 (311,297-342,15)
with 1 N 21-26 at 0.57-0.62; genu 297 (299,286-312,15) with 12-13 a 23-27 at 0.410.81, 1 k 8-10 at 0.95-0.97; tibia 272 (278,257-297,15) 12-14 <f>21-25 at 0.05-0.68, 1
k 7-9 at 0.94-0.96; tarsus 274 (276,255-288,15) with 87-92 o 13-17 at 0.45-0.97, 2-3
fh 40-42 at 0.96-0.98, 2-3 dorsal f 31-35 at 0.68-0.88, 1-2

33-35 at 0.97-0.99.

Leg II 950 (967,918-1007,15), coxal field 165 (167,158-172,15); trochanter 123
(128,118-139,15); basifemur 157 (159,147-163,15); telofemur 159 (152,147-163,15) with
1 N 19-23 at 0.38-0.46; genu 225 (228,217-246,15) with 7-8 a 15-19 at 0.28-0.90, 1 k
8-10 at 0.89-0.92; tibia 173 (178,159-182,15) with 4-5 cf> 17-21 at 0.07-0.54; tarsus 113
(110,107-121,15) with 1 ill 31-33 at 0.95-0.96, 1-2 dorsal f 21-25 at 0.27-0.85, no to
observed.
Leg III 1068 (1048,1008-1123,15), coxal field 165 (163,159-172,15); trochanter
125 (128,117-133,15); basifemur 165 (163,157-172,15); telofemur 173(179,162-188,15)
with 1 N 19-23 at 0.46-0.49; genu 209 (217,199-232,15) with 7-8 a 17-21 at 0.12-0.87;
tibia 268 (272,255-287,15) with 4-5 4> 13-17 at 0.03-0.57; tarsus 129 (131,117-140,15)
with 1 fh 33-35 at 0.92-0.94, no «.
Leg IV 1876 (1882,1723-1988,15), coxal field 260 (268,257-282,15); trochanter

79
130 (129,121-136,15); basifemur 194 (195,183-210,15); telofemur 397 (399,378-421,15)
with 1-2 N 19-23 at 0.37-0.65; genu 366 (357,323-388,15) with 9-10 a 23-27 at 0.170.94; tibia 432 (442,417-452,15) with 8-9 <t> 19-25 at 0.03-0.91; tarsus 357 (362,327388,15) with 1-2 fh 33-35 at 0.91-0.95, no us observed.
Etymology:
The species name honors Dr. W. Calvin Welboum for helping me personally and
for his contributions to Acarology, especially with respect to the classification of
Trombidiidae and Erythraeidae.
Distribution of Types:
The holotype, 20 larval, 20 nymphal and 20 adult paratypes are in Department
o f Zoology, Michigan State University, East Lansing, MI. One larval, nymph and adult
female paratypes will be deposited in each of the following institutions: Department o f
Biology, Fudan University, Shanghai, PRC; Field Museum o f Natural History, Chicago,
IL; National Museum of Natural History, Washington, DC.

Abrolophus channingensis n. sp.
Type series:
Holotype: 1 larva collected from the forest floor on May 15, 1991 parasitizing
a nymph o f a leafhopper, fifteen paratypes collected in the same locality, also parasitizing
nymphs o f leafhoppers o f the same host species. Deutonymphs and adults unknown.

80
Larval description:
Idiosoma: ovoid, length 545 (557,523-588,15). Dorsal setae 46 (47,45-55,15) in length
of 48-56. Ventral setae 42 (42,40-44,15) 31-38.
Prodorsal sclerite (Fig. 39): SM 33 (33,30-36,15), SS 65 (67,63-68,15), AL 44 (45,4247,15),PL 52 (53,50-56,15), AW 59 (61,58-64,15), PW 69 (71,67-74,15), LX 21
(22,19-25,15), ISD 63 (65,62-67,15), ASBa 40 (42,38-44,15), AAS 17 (18,16-19,15),
SBp 13 (14,12-15,15), SBa 12 (12,10-13,15). Eyes 1 + 1, 17 long by 17 wide.
Gnathosoma: palpal femur with 2 setae 35-50; palpal genu with 3 setae 15-23; tibia with
1 seta 21, palpal tibia claw entire; palpal tarsus with 1 long seta 69 (69,67-72,15), 1
cone-like seta 40 (41,38-43,15), 2 short setae 10 each, and 2 stout setae 6 each (Fig. 48).
Legs (Fig. 40a-c): Leg I 395 (388,343-421,10), coxal field 61 (62,60-64,10) with 1 seta
40 (40,38-43,10); trochanter 46 (46,44-48,10), with 2 setae 44 each; basifemur 59
(58,56-62,10) with 4 setae 42-56 long; telofemur 44 (45,42-46,10) with 8 setae 31-33;
genu 82 (83,80-85,10) with 10 setae 29-35, 1 a 15 (15,13-17,10) at 0.79 (0.78,0.770.80,10), 1 k 2 (2,1-3,10) at 0.88 (0.87,0.86-0.89,10); tibia 90 (89,87-93,10), 12 setae
38-40, 2 <f> 21 (19-24,10) at 0.82 (0.82,0.80-0.84,10), 17 (18,16-19,10) at 0.88
(0.87,0.85-0.89,10), 1 k 4 (4,3-5,10) at 0.89 (0.88,0.87-0.90,10); tarsus 71 (71,6873.10) with 22-23 setae 19-33, 1 w 23 (22,20-23,10) at 0.61 (0.60,0.59-0.62,10), 1 fh
47 (45,42-48,10) at 0.75 (0.73,0,70-0.75,10)(Fig. 40a).
Leg I I 356 (360,350-370,10), coxal field 73 (73,70-74,10) with 1 seta 35 (34,3336.10); trochanter 52 (52,50-54,10), with 2 setae 36-40; basifemur 50 (50,48-52,10), 4
setae 31-52; telofemur 36 (37,34-38,10) with 5 setae 35-36; genu 69 (69,67-70,10) with

81
9 setae 21-33, 1 a 15 (15,13-17,10) at 0.76 (0.76,0.74-0.77,10); tibia 88 (89,86-90,10)
with 11 setae 33-36, 2 <j> 17 each at 0.51 and 0.85 respectively; tarsus 59 (59,58-60,10)
with 16 setae 21-31, 1 a> 13 (13,11-15,10) at 0.62 (0.61,0.59-0.63,10), 1 fh 36 (38,3542.10) at 0.78 (0.77,0.75-0.79,10)(Fig. 40b).
Leg III 435 (440,416-452,10), coxal field 69 (68,66-70,10) with 1 seta 38
(38,37-41,10); trochanter 59 (59,58-62,10) with 2 setae 38 each; basifemur 61 (62,6064.10) with 4 setae 35-38; telofemur 52 (52,50-54,10) with 11 setae 42-46; genu 88
(88,85-90,10), 8 setae 33-38, 1 a 17 (17,15-18,10) at 0.80 (0.80,0.78-0.82,10); tibia 117
(118,112-134,10), 11 setae 42-46, 1 4> 19 (19,17-20,10) at 0.08 (0.08,0.06-0.09,10);
tarsus 56 (56,54-57,10), 16 setae 31-42, without specialized setae (Fig. 40c).
Etymology:
The species was named after a small town, Channing in Northern Michigan, near
which collections of this species were made.
D istribution of Types:
The holotype, 5 larval paratypes are in Department of Zoology, Michigan State
University, East Lansing, MI.
Discussion:
The genus Abrolophus was described by acarologists based only on adults.
Larvae and deutonymphs were unknown to science (Womersley, 1934, 1936; Nandmi
Skhot,1968). Unfortunately, most descriptions were simple and incomplete.
These two species o f the genus Abrolophus collected in Michigan represent the
first records for North America, and also the first report correlating larval and adult

82
forms from laboratory rearing. The description of larvae attached to leafhoppers matched
the morphological features of larval Hauptmannia, but adults emerged from reared
nymphs were obviously adult Abrolophus. A careful comparison among hundreds of
larvae and adults confirmed the above Finding.
The same generic designation should therefore be used for both larvae and adults.
However, the relationship between larvae described as Hauptmannia and deutonymphs
and adults of Abrolophus can not be clarified until type specimens of previously
described species can be reviewed.
The major difference separating the two Abrolophus species is the location of two
specialized setae on tibia II; in A. welbourni, they are located at 0.74 and 0.79, and in
A. channingensis, they are located at 0.51 and 0.85 respectively. In addition, the setae
o f the latter are longer than those of the former. Further laboratory rearing of species in
the genus Hauptmannia as defined to date is very necessary.

Charletonia curalia n. sp.
Type series:
Holotype: 1 larva collected from the forest floor on May 21, 1989, fifteen
paratypes collected on 8, 15 May, 1991, 8 May, 1990, 8 May, 1985 and 14 May, 1984.
Nymphs and adults are not known.

83

Larval description:
Idiosoma (Fig. 41a, b): color in life yellow,420 (446,376-510,15) long by 217 (212,208312.15) wide for newly hatched larvae. Body size of engorged larvae varied from 544982 long and 344-566 wide. Dorsal setae 87 in irregular rows, lightly curved and
ciliatious, small and adnate, 38-46 anteriorly, 42-46 posteriorly, and 1 pair of supracoxal
setae in front of dorsal sclerite. Ventral setae la + 2 a + 3 a + 3 b + 3 2 , la 33 (32,30-34,15),
2a 46 (46,44-48,15), 3a 46 (46,43-47,15), 3b 46 (46,44-48,15), setae after leg III 28-34
in number, 42-46 in length. Eyes 1 + 1,21 long by 21 wide, circular, without 2 dorsal
sclerites in the area between eyes and prodorsal sclerite.
Palpal femular; 0+B +B +N B B +4B N w f, 58-25-27,17-15-19, 14 at 0.28, 17 at 0.93,
38 at 0.14, 29 at 0.85 (Fig. 42a, b).
Prodorsal sclerite (Fig. 43):

broader than long, somewhat pentagonal with rounded

angles and with a slightly concave anterior margin; AL,ML and PL equaldistant; AM
anterior to ML, and behind AL; SS arise at the edge of posterior pole of sclerite, no
distinct notch in posterior margin of sclerite.
AL 49 (48,45-50,15), ML 56 (55,52-56,15), PL 59 (59,56-60,15), SM 48 (46,4549.15), SS 52 (52,50-53,15), AW 65 (65,63-66,15), MW 81 (81,78-85,15), PW 100
(98,96-102,15), W 102 (103,100-106,15), L 96 (95,93-96,15),ISD65 (66,63-67,15), SBa
12 (11,10-13,15), SBp 17 (17,15-19,15), ASBa 25 (25,23-26,15), MAS 36 (36,3438.15), PAS 52 (53,50-55,15), ASBM 0, A-M 19 (19,16-20,15), M-P 21 (21,20-23,15),
LX 6 (6,4-7,15), AAS 31 (31,29-33,15), ASBa/ISD 0.38 (0.37,0.35-0.39,15), AW/AL
1.36(1.3,1.1-1.5,15), AW /M -P2.27(2.3,2.15-2.37,15), AW/ISD 1.0(1.0,0.8-1.2,15),

84
ISD/A-P 1.78(1.7,1.5-1.9,15), AL/AAS 1.56 (1.5,1.4-1.8,15), Ti I/AW 1.94 (1.9,1.72.0,15), Ti II/AW 1.69 (1.6,1.4-1.9,15), Ti III/AW 2.44 (2.36,2.2-2.8,15), Ti III/Ge
III 1.5 (1.5,1.2-1.7,15), Ti II/Ge II 1.29 (1.3,1.18-1.33,15), Ti I/Ge I 1.20 (1.2,1.11.32.15), Ti II/PW 1.09 (1.1,1.0-1.3,15).
Legs (Fig. 44a,b,c): Leg 1 525 (520,487-588,15),coxal field 59 (59,55-64,15), lb 56
(55,53-58,15); trochanter 48 (46,45-49,15), IB 46 (47,44-48,15); basifemur 81 (80,7883.15), 4B 40-48; telofemur 63 (64,62-65,15), 5B 35-38 anteriorly, posterior one 36
(36,34-37,15); genu 105 (107,102-112,15), 12B 31-36 anteriorly, 35-36 posteriorly, 1
a 31 (31,28-33,15) at 0.67 (0.66,0.65-0.68,15), 1 k 6 (5,5-7,15); tibia 127 (134,118146.15), 17B 21-31, 2

38 (38,36-39,15) at 0.67 (0.67,0.64-0.69,15), 38 (38,36-39,15)

at 0.87 (0.86,0.85-0.88,15), 1 k 4 (3,3-5,15) at 0.89 (0.88,0.85-0.90,15); tarsus 102
(108,98-112,15), 27B 29-31, 1 u 40 (40,38-43,15) at 0.48 (0.48,0.45-0.50,15), 1
companion seta at 0.66 (0.67,0.64-0.68,15), 1 famulus at 0.85-0.87, 1 f t 36 (36,3437.15) at 0.64 (0.65,0.62-0.67,15), 1 ft) 13 (13,12-15,15) at 0.97 (0.97,0.95-0.98,15),
barbed setae 12-23 in length (Fig. 44a).
Leg I I 465 (458,434-488,15), coxal field 73 (74,71-76,15), 2b 59 (59,56-60,15),
2c 35 (34,33-36,15); trochanter 46 (47,44-49,15), IB 42 (42,40-44,15); basifemur 73
(74,71-75,15), 4B 31-36 in length; telofemur 56 (56,53-58,15), 5B 27-31 from anterior
region to posterior region; genu 84 (85,82-86,15), 12B 29-31, 1 k 6 (5,4-7,15); tibia 109
(109,98-107,15), 18B 29-31, 2 <t> 29 (28,25-29,15) at 0.12 (0.12,0.11-0.14,15), 15
(15,13-16,15) at 0.84 (0.85,0.82-0.86,15); tarsus 96 (98,92-102,15), 27B 31-33, 1 o> 23
(23,22-25,15) at 0.58 (0.58,0.55-0.60,15), 1 famulus at 0.87-0.90, 1 f t 13 (13,12-15,15)

85
at 0.94 (0.95,0.92-0.97,15), barbed setae 17-27 (Fig. 44b).

86

Figs. 41-44. Charletonia curalia n. sp. (larva):
41a-b. dorsal and ventral idiosoma;
42a-b. palpals and palpal tibia and tarsus;
43. prodorsal sclerite;
44a-c. leg I-III genu to tarsus.
Scale lines fir Figs. 41a-b, 44a-b represent 100 /xm each; scale lines for Fig. 42a-b, 43
represent 50 /xm.

87

Jm \
m

m

/

w

\

MU

88
Leg III 575 (553,522-612,15), coxal field 71 (72,70-74,15), 3c 52 (52,50-54,15),
3d 40 (40,38-43,15); trochanter 54 (54,52-55,15), IB 44 (44,41-45,15); basifemur 81
(80,78-84,15), 2B 42-58; telofemur 73 (73,70-75,15), 5B 31-35; genu 100 (99,96104.15), 12B 35-38 anteriorly, 35-36 posteriorly, without solenidia; tibia 163 (165,153187.15), 18B 35-36 anteriorly, 33-36 posteriorly, 1 <f>27 (26,24-28,15) at 0.07
(0.06,0.05-0.08,15); tarsus 107 (107,102-119,15), 28B 33-35, 1 subterminal seta at 0.970.99, no w and to (Fig. 44c).
Etymology:
The species name was derived from a Latin word, curalium, for the red coral
color which impressed me when I collected a leafhopper with the mite larva attached.
Discussion:
This genus is an important, difficult and large one. In a major generic study,
Oudemans (1910a, b) placed three of nine species of larval Charletonia in Charletonia,
but later (1910c, 1912) he placed them in Erythraeus Latreille, 1806.
Later still, other species were described from larvae by Kishida (1929),
Womersley (1934), Feider (1954) and Lawrance (1940) under Erythraeus, by Paoli
(1937) under Balaustium von Heyden, 1826, and by Kawashima (1958) and Kitahara &
Takara (1964) under Callidosoma Womersley, 1936.
In addition, Ishii (1954) reared deutonymphs of an undetermined Sphaerolophus
species from larvae found on grasshoppers in Japan, and sent drawings of both larvae and
nymphs to Southcott. Southcott (1966) later discussed the possible synonymy of the two
generic names, but preferred "to leave the adults and larvae in their own generic

89
categories."
Southcott (1966) also revised the taxonomy of the genus and studied Oudemans’
collections from Holland and northern Germany. He stated that all specimens considered
by Oudemans under "Erythraeus larval" came under the definition of Charletonia. At that
time, the genus was thus left with 32 species, comprising 5 European, 7 African, 5
Asian, and 16 Australasian forms. No North or South American material was known.
In 1979, Treat and Flechtmann described the first Charletonia from Brazil,
Charletonia rocciai, an ectoparasite o f the Amazon fly Metagonistylum minense
Townsend, 1927 (Diptera, Tachinidae).
One year later, Rosa and Flechtmann illustrated that the morphological features
o f nymphs reared from larvae of Charletonia rocciai clearly represented the genus
Sphaerolophus (Erythraeidae: Trombidia).
Meanwhile, Treat (1980) noticed that a deutonymph reared from a larva closely
resembling Charletonia singularis Oudemans conformed to Sphaerolophus cardinalis
(Koch) as redescribed by Franke (1940) and Witte (1977) in Germany. Treat suggested
that "It appears probable that Charletonia singularis is the larval form o f cardinalis."
Since then, subsequent descriptions of larvae have been published by Beron
(1975), Treat & Flechtmann (1979), Treat (1980), Southcott (1983,1988,1991),
Haitlinger (1984,1985,1986,1987) and Tsai & Chow (1988) as Charletonia.
Currently, the genus has over 50 species described as larvae, collected either
free-living or as ectoparasites of arachnids and insects from every continent except
Antarctica. Confirmation of the proposed synonymy (Charletonia= Sphaerolophus) was

90
given by four further larva to deutonymph rearings: in North America of adult C.
cardinalis (Koch) with its larva C. singularis (Oudemans) by Treat (1980); and of C.
nishidai by Southcott (1983); in South America of C. rocciai by Rosa & Flechtmann
(1980); and of C. oudemansi by Southcott (1988). In addition, there are 22 species
described as adults of Sphaerolophus for which the corresponding larvae and nymphs are
yet to be obtained.
The species collected in Michigan resembles Charletonia singularis Oudemans
closely. The latter was found on a noctuid moth, Simyra henrici (Grote), in
Massachusetts. Some differences which distinguish curalia, singularis, and rocciai are
listed in Table 7. Measurements used here follow Southcott’s terms, such as ratios of
length of tibia I over body width, length of tibia I over that of tarsus I and data for the
prodorsal sclerite.

91
Table 8. Main character differences between three American Charletonia species:
measurement of length of sclerite and leg segments; ratio of the length of leg segments
and of sclerite.

characters
Til/W
Til/Tal
PW/AW
AW/AL
AW/ISD
AL/PL
MW
ASE
PSE
SBa
SBp
AL
Idiosoma
Leg IIBf
Ti
Leg III Cx
Bf

curalia (MI)

singularis (MA)

rocciai (BZ)

0.58
1.25
1.43
1.36
1.0
0.80
80
48
51
11
17
47
420
73
109
71
81

1.21-1.38
1.18
1.56-1.58
1.07
0.92
1.03
95
56-62
63-64
15
17
57
271
63
112
59
72

1.1-1.17
0.86-0.94
1.31-1.34
1.66
1.32
0.96
80-82
32
65
11
20
47
552
61
104
78
72

Charletonia curalia differs from rocciai in having smaller ratios of Til/AW,
AW/ISD, AL/PL, shorter PSE and idiosoma; larger Til/Tal ratio, longer ASE, leg II,
Bf II, leg III and Bf III. It differs from singularis in having smaller Til/W , PW/AW,
AL/PL ratios, shorter MW, ASE, PSE, SBa and AL; and in having larger idiosoma,
Til/Tal and AW/AL ratios, longer leg II, Ti II, leg III, CX III and Bf III.

92
Distribution of Types:
The holotype, 10 larval paratypes are in Department of Zoology, Michigan State
University, East Lansing, MI. One larval paratype will be deposited in Field Museum
o f Natural History, Chicago, IL.

Subfamily Balaustiinae:
Balaustium nortasum n. sp.
Type series:
Holotype and 15 paratype larvae collected from the forest floor on June 4, 6, 9,
II o f 1990. Five paratype adults collected from the same site.
Larval description:
Idiosoma (Fig. 45a, b): color in life red, 385 (390,375-423,15) long by 230 (247,228257.15) wide, dorsal setae 83 (87,80-94,15) in number, 46-56 anteriorly, 46-48
posteriorly, ventral setae la + 2a + 3a + 22 (25,21-37,15) between coxal field II and
III + 38 (34,31-38,15) after coxal field III, la 63-65, 2a 38-40, 3a 36-54, ventral setae
36-42.

Eyes 1 + 1, 15 (16,15-17,15) long by 15 (16,15-18,15) wide. Palpal setae

formula B-B-BB-NNN-B3Na>f (Fig. 46a, b, c).
Prodorsal sclerite (Fig. 47): AM 63 (61,60-64,15), SS 84 (84,82-85,15), AL 40 (40,3842.15), ML 36 (36,34-38,15), PL 46 (47,44-48,15), AW 43 (42,38-44,15), MW 44
(43,42-45,15), PW 59 (56,55-59,15), L 107 (109,103-117,15), LX 4 (4,3-5,15), ISD 65
(67,62-77,15), SBa 15 (14,13-15,15), SBp 17 (16,14-18,15), ASBa 6 (7,5-12,15).
Legs (Fig. 48a, b, c): Leg I 426 (430,418-450,15); coxal field 59 (55,53-59,15), IB 54-

93
55,15; trochanter 48 (45,42-49,15), 3B 50-61; basifemur 65 (66,64-69,15), 4B 44-58;
telofemur 65 (60,53-67,15), 6B 48-54; genu 79 (87,75-98,15), 1IB 42-67, 1 a 35 (30,2336.15) at 0.80 (0.80,0.78-0.84,15), 1 k 6 (6,5-7,15) at 0.83 (0.87,0.80-0.90,15); tibia
98 (98,96-103,15), 13B 38-52, 1 <t>27 (25,24-27,15) at 0.76 (0.74,0.73-0.77,15), 1 k
6 (6,5-8,15) at 0.88 (0.86,0.84-0.87,15); tarsus 75 (77,73-84,15), 24-26B 31-40, 1 a 42
(42,40-43,15) at 0.61 (0.57,0.55-0.63,15), 1 *ti 48 (45,42-47,15) at 0.79 (0.78,0.750.79,15), 1 ip 23 (22,20-24,15) at 0.92 (0.91,0.90-0.94,15), 1 c 8 (11,7-13,15) at 0.79
(0.77,0.75-0.79,15), 9 f 21-25 at 0.43-0.87 (Fig. 48a).
Leg I I 351 (355,324-376,15), coxal field 79 (83,76-92,15), IB 50 (50,46-56,15);
trochanter 36 (45,34-53,15), 3B 42-57; basifemur 54 (51,48-55,15), 4B 44-54; telofemur
42 (41,40-43,15), 6B 40-54; genu 77(76,73-78,15), 1IB 42-67, 1 k 6 (6,5-7,15) at 0.90
(0.90,0.88-0.92,15); tibia 73 (75,71-80,15), 13B 36-52, 1 0 19 (18,16-20,15) at 0.70
(0.72,0.70-0.77,15); tarsus 69 (69,67-73,15), 21-23B 21-48, 1 w 19 (19,17-20,15) at
0.60 (0.56,0.51-0.62,15), 1 fh 38 (39,37-42,15) at 0.78 (0.75,0.73-0.80,15), 1 ip 23
(22,20-24,15) at 0.87 (0.88,0.85-0.90,15), 4 f 23-25 at 0.47-0.87, 1 c 12 (11,9-13,15)
at 0.73 (0.73,0.70-0.74,15)(Fig. 48b).
Leg III 407 (414,403-435,15), coxal field 84 (86,82-92,15), IB 50-52; trochanter
40 (47,40-53,15), 3B 48-56; basifemur 61 (58,57-63,15), 3B 46-54; telofemur 50 (50,4653.15), 6B 38-54; genu 90 (87,83-92,15), 9B 42-52, no solendia observed; tibia 98
(98,96-102,15), 13B 44-54, 1 <t>27 (25,24-27,15) at 0.12 (0.12,0.11-0.14,15); tarsus 69
(73,68-75,15), 18-21B 21-48, 1 ip 23 (22,20-23,15) at 0.89 (0.92,0.88-0.96,15), 1 f a t
ventral region 0.25 (0.25,0.23-0.26,15), 25 (24,22-25,15) in length (Fig. 48c).

94
Deutonymph:

unknown.

Adult female (Fig. 49-52):
Idiosoma measured from tip of mouthpart to posterior pole 1795 (1642,14781985.5) long by 936 (932,877-985,5) wide, two types of setae on the body: long smooth
setae and shorter barbed setae, more long setae at rear, setal length 48-90 anteriorly, 5481 posteriorly; ventral setae 82-178 anteriorly, 73-102 posteriorly in length. Genital
valvels with many setae, anal valvel with a few setae (Fig. 49).
Eyes: 1 + 1 at each side, 38 wide, and 42 long. A pair of urnula next to eyes (Fig. 50).
Gnathosoma (Fig. 51a, b): palpal genu 178 (173,168-189,5) long, anterior setae 44-54
in length, posterior setae 42-46, 6 long setae at 0.35-0.56, 77-98 in length, 3 long setae
at front edge 0.73-0.84, 48-77 long; palpal tibia 140 (138,134-147,5), anterior setae 3652, posterior setae 35-52, tibia claw entire, 27 (25,23-27,5) long, 1 tooth at middle 0.50,
2 long setae 50-61 at 0.67, 0.89; palpal tarsus 56 (55,52-58,5), 15-17 w 13-19 anteriorly,
21-23 posteriorly, at 0.38-0.99, among them, 4 long w at rear 0.38-0.45, the rest in midto front region, 6-7 f a t 0.33-0.78.
Prodorsal sclerite (Fig. 52):

316 (302,297-325,5) long by 140 (138,129-143,5) wide,

with 6 front setae anterior to AM, 94-125, AM 102 (102,96-105,5), AL 102 (97,95103.5), AW 56 (55,52-57,5), MW 123 (121,118-124,5), ML 109 (108,104-109,5), PL
90 (90,88-91,5), PW 190 (188,185-191,5), SS 139 (140,135-143,5), SBa 19 (18,1619.5), SBp 19 (19,17-19,5), ISD 198 (195,187-203,5), LX 67 (67,65-69,5), ASBa 44
(44,40-46,5), A 63 (63,60-64,5), B 73 (74,72-76,5).

95

Figs. 45-47 Balaustium nonasum (larva):
45a-b. dorsal and ventral idiosoma (larva);
46a-d. pal pals (larva);
47. prodorsal sclerite (larva);
Scale lines for Figs. 45a-b, 46a, 49, 50, 52 each represent 100 j*m, scale lines
for Fig. 46b-d, 47, 51 each represent 50 /*m.

»

m

96

97

Figs. 48, Balaustium nonasum n. sp. (larva):
48a-c. legs I-III (larva).
Scale line represents 100 ^m .
Figs. 49-52. Balaustium nonasum n. sp. (adult female):
49. genital and anal valves (adult female);
50. eye (E) and umula (u)(adult female);
51a. palpals (adult female);
51b. palpal tarsus (adult female);
52. prodorsal sclerite (adult female).
Scale lines represent 100 /xm.

98

i50

i

4

l

'

m

99
Leg I:

1482 (1384,1278-1780,5) long, coxal field 198 (194,185-213,5), 98-161

anteriorly, 69-79 posteriorly; trochanter 163 (166,157-173,5), setae 75-84 anteriorly, 4854 posteriorly; basifemur 199 (194,187-216,5), setae 63-77 anteriorly, 61-81 posteriorly;
telofemur 282 (238,219-298,5), setae 59-67 anteriorly, 61-79 posteriority, 3 N 65 (65,6266.5) at 0.48 (0.46,0.42-0.49,5), 67 (67,64-68,5) at 0.71 (0.71,0.68-0.73,5), 69 (69,6770.5) at 0.89 (0.88,0.85-0.90,5); genu 320 (318,307-348,5), setae 65-81 anteriorly, 5965 posteriorly, 3 N 82 (83,80-86,5) at 0.53 (0.52,0.50-0.54,5), 67 (67,65-68,5) at 0.68
(0.67,0.65-0.69,5), 71 (71,69-72,5) at 0.85 (0.84,0.81-0.87,5), 8 a 32-40 at 0.48-0.95;
tibia 316 (309,302-323,5), setae 63-69 anteriorly, 71-81 posteriorly, 10 N 65-73 at 0.070.89, 4 <f>38-40 at 0.35-0.70, 3 k 6-8 at 0.60-0.80, 6 </> at ventral, 33-40 at 0.12-0.67;
tarsus 199 (192,187-212,5), setae 42-44 anteriorly, 42-48 posteriorly, 1 oi 19 (19,1720.5) at 0.80 (0.80,0.78-0.81,5), 17-19 u 23-33 at 0.59-0.88, 4 f 58 (57,55-58,5) at
0.62 (0.61 0.60-0.62,5), 61 (62,60-64,5) at 0.77 (0.76,0.75-0.79,5), 59 (60,58-63,5) at
0.79 (0.78,0.76-0.80,5), 2 f 61-73 at 0.95-0.98, 2 ft) 42 each at 0.96, and 0.98, 16-18
f 29-40 at 0.11-0.82 ventrally.
Leg II:

1102 (1098,1089-1210,5), coxal field 244 (238,225-246,5), setae 73-77

anteriorly, 58 for a long seta at rear region; trochanter 135 (132,128-142,5), 77-82
anteriorly, 69-102 posteriorly, long setae 139 (137,130-142,5) at middle; basifemur 144
(140,137-148,5), 56-69 anteriorly, 48-59 posteriorly, with a long seta 94 at anterior
region; telofemur 192 (187,179-194,5), 73-77 anteriorly, 50-58 posteriorly, with 1 N 61
(60,58-62,5)at 0.87 (0.86,0.85-0.88,5);genu 207 (204,200-210,5), 75-81 anteriorly, 5459 posteriorly, 3 N 58 (57,55-59,5) at 0.55 (0.54,0.53-0.56,5), 52 (52,50-54,5) at 0.64

100

(0.63,0.60-0.65,5), 58 (57,55-58,5) at 0.89 (0.88,0.86-0.90,5), 2 a 29 each at 0.50, and
0.87, 1 k 10 (10,8-11,5) at 0.73 (0.73,0.71-0.75,5); tibia 274 (270,258-288,5), 61-79
anteriorly, 67-81 posteriorly, 4 N 59-79 at 0.16-0.89, 1 <f> 15 (15,14-17,5) at 0.72
(0.71,0.69-0.73,5); tarsus 150 (142,138-152,5), 50-58 anteriorly, 40-50 posteriorly, 5
to 13-17 at 0.68-0.81, 3 f 52 (52,50-53,5) at 0.88 (0.86,0.85-0.89,5), 58 (57,55-59,5)
at 0.91 (0.89-0.93,5), 69 (69,67-69,5) at 0.93 (0.92,0.90-0.94,5), 2-3 f 50-58 at 0.910.94 anteriorly, 1 {*50 (49,45-49,5) at 0.82 (0.81,0.80-0.83,5), 5-6 f 33-38 at 0.20-0.67
ventrally.
Leg III:

1188 (1153,1096-1230,5), coxal field 242 (238,212-247,5), setae 75-82

anteriorly, 178 for a long

seta at rear; trochanter 130 (128,119-132,5), 73-102

anteriorly, 69-88 posteriorly; basifemur 127 (126,118-134,5), 55-66 anteriorly, 63-72
posteriorly; genu 278 (258,230-282,5), 67-84 anteriorly, 67-69 posteriorly, 2 N 61
(61,58-63,5) at 0.45 (0.45,0.43-0.46,5), 71 (71,69-72,5) at 0.57 (0.56,0.54-0.58,5), 2
a 13-21 at 0.34-0.59; tibia 263 (257,238-265,5), 59-63 anteriorly, 58-69 posteriorly, 4
N 54-63 at 0.10-0.90, 4 <*> 23-31 at 0.05-0.43; tarsus 127 (122,118-132,5), 42-48
anteriorly, 42-52 posteriorly, 2 a> 10-12 at 0.54, 0.65, 4 f 35-48 at 0.21-0.76, 2-3 f4 8 52 at 0.86-0.90.
Leg IV: 1396 (1347,1307-1402,5), coxal field 276 (263,243-282,5), 54-65 anteriorly,
long seta 79 in length; trochanter 88 (86,84-90,5), 79-98 anteriorly, 58-63 posteriorly;
basifemur 182 (179,168-188,5), 65-77 anteriorly, 65-67 posteriorly, long setae 77 at
anterior region; telofemur 301 (297,268-303,5), setae 84-90 anteriorly, 58-65 posteriorly,
4 long setae 86-106 at 0.48-0.71; genu 328 (315,308-333,5), setae 77-90 anteriorly, 61-

101
69 posteriorly, 3 N 79 (76,75-79,5) at 0.54 (0.53,0.50-0.56,5), 84 (83,80-85,5) at 0.29
(0.28,0.27-0.30,5), 90 (89,87-92,5) at 0.90 (0.88,0.87-0.93,5), 5 o 35-36 at 0.17-0.75;
tibia 355 (352,344-363,5), setae 67-71 anteriorly, 67-69 posteriorly, 4 N 86 (85,84-87,5)
at 0.26 (0.25,0.23-0.27,5), 92 (92,90-94,5) at 0.57 (0.56,0.54-0.58,5), 84 (84,82-85,5)
at 0.66 (0.65,0.63-0.67,5), 69 (67,65-69,5) at 0.76 (0.75,0.74-0.78,5), 4 <f> 29-38 at
0.04-0.32; tarsus 142 (140,132-150,5), setae 56-71, 2 £63-69 at 0.75, 0.86, 2 £ 56-58
at 0.82-0.88 anteriorly, 1 £35 (34,30-34,5) at 0.30 (0.30,0.28-0.34,5).
Discussion:
The cosmopolitan genus Balaustium was first described by Von Heyden (1826)
with Trombidium murorum Hermann, 1804 as type species. In the last four decades, a
number of reports of feeding behavior attracted much attention to several important
studies both in field and laboratory.
However, our knowledge of the systematics of the genus is relatively incomplete.
Descriptions of most species are brief and the diagnostic characters are so little known
that it is impossible to say at the present time how many species are involved. Among
50 named species from all over the world, a number of them are likely to be
synonymous.
Balaustium nonasum differs from B. putmani Smiley by a palpal tarsus which is
not longer than the tibia, with 8 instead of 10-12 solenidia apically; crista without 9
"stout serrated setae anteriorly to the anterior sensory setae"; lack of fine distinct
ornamentation of the striae anteriorly to the crista;
arising from nose-like projections of scutum.

and posterior sensory setae not

102
The species differs from B. dowelli Smiley by the presence o f three to four long
setae anterior to AM setae, seven pairs of setae on sclerite between AM and SS setae;
tibia I with 10-12 long, slender, nude setae at ventral lateral, 7 long setae at dorsal leg.
Etymology:

The species name was derived from a Latin word, nonasum, meaning

without nose-like projections on sclerite.
D istribution o f Types:
The holotype, 10 larval and 3 female paratypes are in Department of Zoology,
Michigan State University, East Lansing, MI. One larval and female paratype will be
deposited in Field Museum of Natural History, Chicago, IL.
<v

A new genus and a new species separated from the related genus Catena
Type series:
Holotype: 1 larva collected on May 20,1991 from the forest floor. Fifteen
paratypes collected from same location from May 16 to June 4, 1987 and 1991.
Unfortunately larval hosts were not found with the mites. Fifteen paratype adults
collected during July and August of 1990 and 1991. Laboratory rearing for deutonymphs
failed.
L arval description:
Idiosoma:

color in life yellow. Ellipsoid, 604 (655,600-730,15) long from mouthpart

to pole o f the body, 356 (325,310-370,15) wide between legs II and 284 (321,270350,15) wide between legs III. Two pairs of eyes set in an ocular sclerite on each side
of prodorsum, anterior eye 25 (26,23-27,15) long and 21 (20,18-24,15) wide, posterior

103
eye 21 (22,19-24,15) long and 25 (24,22-26,15) wide. Dorsum hypertrichous with 36
(38,34-40,15) dorsal setae in length from 69 to 73 anteriorly, and 69 to 84 posteriorly
(Fig. 53a).
Ventral idiosoma with 1 pair (la) of intercoxal setae between coxal field I, 71
(71,68-74,15), and one pair (3a) between coxal field III, 46 (47,44-49,15); seta lb on
coxal field leg I, 52 (53,50-55,15); coxal fields of legs II and III each with 1 seta (2b and
3b), 56 (57,54-58,15) and 59 (59,56-60,15) respectively; 18 setae behind coxal field III
in length 50-58 anteriorly and 56-59 posteriorly (Fig. 53b).
Prodorsal sclerite (Fig. 54):

136 (138,134-139,15) long, 163 (165,157-170,15) wide,

AW 61 (63,60-65,15), PW 146 (147,138-155,15), AM 38 (39,35-40,15), SS 90 (90,8793.15), AL 161 (158,156-164,15), PL 81 (78,76-83,15), SBa 33 (33,31-35,15), SBp 23
(24,21-25,15), LX 35 (35,32-36,15), ISD 77 (78,74-79,15).
Palpals (Fig. 55a, b, 56a, b): palpal femur with 1 B seta 63 (57,52-73,15) long, palpal
genu with 1 B seta 52 (52,48-58,15) long, paltibia with 1 B seta and 2 nude setae, tibial
claw bifurcate,

palpal tarsus with 4 nude setae, 1

and 1 ta. Palpal formular =

B +B +B N N +co4N N , tip of mouthpart with fringes, 128 (132,117-143,15) long.
Legs (Fig. 57a, b, c):
Leg I from trochanter to pretarsus 887 (888,854-927,15) long, coxal field 109
(107,105-120,15) with IB; trochanter 86 (85,83-88,15) with IB 69 (72,68-75,15);
basifemur 130 (132,129-134,15) with 3B 84-98; telofemur 107 (108,105-110,15) 5B 7582; genu 188 (190,179-195,15) 8B 75-71, 1 a 29 (29,26-31,15); tibia 280 (287,278298.15) with 13B 58-81, 2

36 (32,29-36,15) at 0.72 (0.72,0.70-0.74,15), 36 (34,29-

104
37.15) at 0.83 (0.83,0.82-0.85,15), 1 k 8 (7,6-8,15) at 0.92 (0.94,0.91-0.97,15); tarsus
163 (168,158-170,15) with 25B 23-40, 1 «31 (32,27-34,15) at 0.55 (0.53,0.50-0.56,15),
1

40 (40,38-43,15) at 0.91 (0.92,0.89-0.93,15), 1

31 (30,28-35,15) at 0.96

(0.96,0.93-0.98,15) and 1 e 12 (11,10-14,15) at 0.91 (0.92,0.90-0.93,15)(Fig. 57a).
Leg II 957 (972,940-980,15) long, coxal field 105 (108,102-112,15) with IB;
trochanter 69 (72,68-74,15) with IB 63 (63,60-65,15); basifemur 148 (150,145-160,15)
with 3B 86-92; telofemur 139 (142,138-147,15) with 5B 36-81; genu 152 (154,150158.15) with 8B 71-81, no specialized setae observed; tibia 280 (285,278-290,15) with
13B 63-73, 2 <f>29 (29,26-30,15) at 0.06 (0.05,0.05-0.07,15), 19 (20,18-23,15) at 0.92
(0.93,0.90-0.95,15);tarsus 159 (162,158-170,15) with 13B75-90, 1 w21 (22,20-24,15)
at 0.47 (0.48,0.45-0.50,15), 1 fh 40 (42,39-44,15) at 0.83 (0.84,0.80-0.85,15), 1 fp31
(32,30-34,15) at 0.89-0.92 (Fig. 57b).
Leg III 1045 (1100,1000-1256,15) long, coxal field 125 (126,120-130,15) with
IB; trochanter with IB 71 (72,70-75,15), 75 (76,73-78,15) long; basifemur 143
(144,140-152,15) with 3B 65-88; telofemur 135 (140,130-151,15) with 5B 82-94; genu
178 (180,172-187,15) with 8B 82-90, without a\ tibia 338 (340,335-353,15) with 13B
75-90, 1 <f>29 (29,27-30,15) at 0.04 (0.03,0.02-0.05,15); tarsus 180 (184,178-186,15)
with 21B 29-61, without w and f (Fig. 57c).
Deutonym ph: unknown.
Adult female (Fig. 58-60):
Idiosoma: color in life yellowish brown to brown. Ellipsoid, 1026 (1104,1008-1270,15)
long by 645 (650,638-680,15) wide between coxal leg II, 739 (750,727-780,15) wide

105
between coxal leg III. One pair of eyes set in a sclerite on each side of prodorsum, 38
(38,36-40,15) long by 27 (27,25-30,15) wide. Dorsum with setae 21-27 in length
anteriorly, 19-29 in length posteriorly.
Gnathosoma: anterior end o f gnathosoma with 5 pairs o f nude setae 12-38 in length and
fingerlike fringe.
Palpals: trochanter 46 (47,45-50,15) with 14 setae 25-42; femur 132 (135,130-141,15)
with 38-45 setae 29-44; genu 86 (85,83-88,15) with 32-36 setae 23-52 long; tibia 63
(64,60-66,15) with 23-25 setae 17-35; tarsus 42 (43,40-44,15) with 27-29 setae 12-17.
Legs:

Leg I 2187 (1997,1768-2238,5), coxal field 257 (238,226-266,5); trochanter

190 (185,157-191,5), setae 48-82 in length; basifemur 288 (284,253-297,5), 42-48 for
most setae, 75 for a long seta; telofemur 394 (375,355-418,5), setae 46-59, 71 for a long
setae, 1 N 54 (54,50-55,5) at 0.66 (0.64,0.62-0.67,5); genu 509 (488,476-508,5), setae
56-63 in length, 7 a 42 (42,40-44,5) at 0.25 (0.25,0.23-0.26,5), 38 (38,35-39,5) at 0.26
(0.26,0.24-0.27,5), 42 (42,40-43,5) at 0.53 (0.53,0.51-0.54,5), 54 (54,52-55,5) at 0.68
(0.67,0.66-0.70,5), 35 (34,33-35,5) at 0.69 (0.68,0.67-0.70,5), 54 (54,52-55,5) at 0.84
(0.83,0.82-0.85,5), 52 (52,50-54,5) at 0.82 (0.83,0.80-0.84,5); tibia 486 (456,424497.5), setae 56-71, 39 <t>25-48 at 0.23-0.88 region; tarsus 320 (316,296-340,5), two
types setae at the region, barbed setae 13-19 in length, nude setae 17-19, 2 f 67 (67,6469.5) at 0.87 (0.86,0.84-0.89,5), 50 (48,46-50,5) at 0.92 (0.91,0.90-0.93,5), 18 u 38-40
in length at 0.26-0.88 region.
Leg II 1497 (1208,1094-1563,5), coxal field 212 (217,208-225,5); trochanter 152
(147,142-154,5), setae 48-69, long setae 90 at anterior end; basifemur 163 (160,154-

106
165,5), setae 52-75; telofemur 275 (267,259-278,5), 3 N 40 (40,38-42,5) at 0.64
(0.63,0.62-0.65,5), 54 (54,52-55,5), 56 (56,53-56,5) at 0.93 (0.93,0.91-0.94,5); genu
330 (327,310-340,5), setae 63-82 in length, 5 a 44 (44,42-46,5) at 0.50 (0.51,0.490.54,5), 44 (44,42-45,5) at 0.66 (0.65,0.64-0.67,5), 46 (46,44-47,5) at 0.79 (0.78,0.760.79,5), 46 (46,42-46,5) at 0.86 (0.85,0.83-0.87,5), 50 (49,47-50,5) at 0.90 (0.91,0.890.93,5); tibia 357 (343,314-376,5), setae 52-71, 12 4> 15-52 at 0.38-0.83 dorsal, 2 <t>2740 at ventral 0.71-0.87; tarsus 215 (208,197-226,5), 8 f 17-27 at 0.24-0.89 dorsal, 1 f
40 (40,38-42,5) at 0.94 (0.93,0.92-0.95,5), 1 to 46 (46,44-47,5) at 0.74 (0.72,0.700.76,5).
Leg III 1567 (1365,1206-1783,5), coxal field 232 (238,225-244,5); trochanter 213
(207,198-231,5), setae 40-86; basifemur 150 (143,139-152,5), setae 42-56 from posterior
to anterior area; telofemur 226 (217,205-234,5), setae 59-79, 4 N 46-56 in length at
0.51-0.75; genu 357 (322,305-378,5), setae 56-63, long setae 92-97, 2 a 25-33 at 0.370.46; tibia 394 (347,328-412,5), 8 0 36-58 at 0.52-0.90 dorsal, 3 4>40-56 at 0.72-0.75

107

Figs. 53-56. a new genus and new species related to Cuteria (larva):
53a-b. dorsal and ventral idiosoma;
54. prodorsal sclerite;
55a. dorsal gnathosoma;
56a-b. palpals.
Scale lines for Fig. 53, 55a each represent 100 /*m. Scale lines for Figs. 54, 56a-b each
represent 50/xm.

Figs. 55b. 57. a new genus and species related to Cuteria (larva):
55b. ventral gnathosoma;
57a-c. legs I-III genu to tarsus.
Scale lines for Figs. 56b, 57 each represent 100 /x.

108

109

Figs. 58-60. a new genus and new species related to Cuteria (adult female):

58. prodorsal sclerite and eyes (female);
59. gnathosoma (female);
60. palpals (female).

Scale lines each represents 100 /*m.

o
o

Ill

ventral; tarsus 226 (207,198-233,5), setae 65-71, 1 o 46 (46,43-47,5) at 0.74 (0.73,0.720.75,5), 3 small f 8-19 at 0.18-0.69, 1 *1i 46 (44,42-47,5) at 0.97 (0.96,0.95-0.98,5),
1 ip 36 (36,34-37,5) at 0.98 (0.97,0.96-0.99,5).
Leg IV 1525 (1436,1279-1785,5), coxal field 274 (264,257-293,5); trochanter 163
(153,138-179,5), 48-50 posteriorly, long setae 73-76 anteriorly; basifemur 134 (128,120141.5), 48-50 posteriorly, 69-72 for long setae anteriorly; telofemur 155 (148,136162.5), 46-49 posteriorly, 67-69 anteriorly, 1 N 40 (40,38-42,5) at 0.48 (0.46,0.440.49,5), 2 N 44 (44,42-46,5) each at 0.91 (0.90,0.88-0.92,5) seperately; genu 322
(312,298-331,5), 54-56 posteriorly, 71-73 anteriorly, dorsal region with 3 a 23 (23,2125.5) at 0.13 (0.13,0.11-0.14,5), 25 (25,22-26,5) at 0.23 (0.23,0.21-0.24,5), 25 (24,2225.5) at 0.33 (0.32,0.30-0.34,5), 3 large 52 (51,50-54,5) at 0.55 (0.54,0.51-0.56,5), 33
(33,31-34,5)a t 0.64 (0.63,0.60-0.65,5),58 (58,55-59,5)at 0.91 (0.90,0.88-0.93,5);tibia
591 (588,557-604,5),setae 73-84, 6 <f> 21 (21,20-23,5) at 0.06 (0.05,0.04-0.07,5), 25
(25,23-26,5) at 0.10 (0.10,0.08-0.11,5), 38 (38,35-39,5) at 0.19 (0.18,0.17-0.20,5), 44
(44,42-46,5) at 0.30 (0.30,0.29-0.32,5), 56 (55,52-57,5) at 0.66 (0.65,0.62-0.67,5), 50
(49,46-50,5) at 0.89 (0.88,0.86-0.90,5); tarsus 1574 (1537,1429-1678,5), 5 f 33-38 at
0.64-0.68, 1 f 17 (17,15-18,5) at 0.31 (0.30,0.30-0.33,5) ventrally, 2 fh 58 (57,55-58,5)
at 0.93 (0.93,0.90-0.94,5), 59 (59,57-60,5) at 0.97 (0.97,0.95-0.98,5), 1 ip 27 (27,2428.5) at 0.99 (0.98,0.96-0.99,5), no u observed.
Discussion:
The genus Cuteria was erected based on Algerian specimens by Cooreman (1956),
with the type species Cuteria fageli which was a synonym of Morieria curticristafa from

112
Austria, Switzerland and Greece. Southcott (1961) redescribed the genus Cuteria with
several species.
The specimens differ from genus Cuteria in many characters. Main character is
that on prodorsal sclerite of larvae, two short sensory setae located concaved ditches,
which is not presented in other genera.

Subfamily Allothrombiinae
Allothrombium carum n. sp.
Type series:
The holotype hatched on July 5, 1991 from egg batches laid by a female on June
18, 1991. Fifteen paratypes came from the same egg batches as well as other clumps laid
on May 28, June 15, 26, 28 and 30, 1991. Deutonymphs and adults are not available.
Larval description:
Color: in life red. Idiosoma414 (426,402-468,15) long by 232 (228,212-247,15) wide.
Nineteen dorsal setae 48-58 in length, ventral setae 3a 61 (62,60-67,15) + 9-10 setae
behind coxal field III, 44-61 long (Fig. 61a, b).
Palpals: palpal femur 29 (29,26-31,15) with 1 seta 38 (37,35-39,15); palpal genu 12
(12,10-13,15); palpal tibia 13 (14,12-15,15) with 3 nude setae, palpal tibia claw bifurcate
distally; palpal tarsus 13 (14,12-16,15), 2 setae 25-44, 1 w 2 (2,1-3,15) and 1 nude seta
17 (16,15-18,15)(Fig. 62a, b).
Prodorsal sclerite: 127 (129,118-133,15) long by 121 (122,118-132,15) wide, AW 82

113
(83,80-86,15), PW 96 (96,93-99,15), SE52 (53,50-55,15), AL 54 (55,51-57,15), PL 63
(64,61-65,15), SB 59 (58,55-61,15), A-P 35 (35,33-36,15), A-S 15 (15,14-17,15), LX
65 (66,61-66,15), ISD 52 (53,50-55,15). Eyes 2 + 2, 29 (29,26-31,15) long by 13
(13,12-15,15) wide (Fig. 63).
Legs (Fig. 64a-c):
Leg I

316(318,309-327,15), coxal field 61 (63,60-65,15) with la 67 (68,62-

70.15) and lb

56 (56,52-58,15); trochanter 44 (45,42-46,15) with 1 seta 48 (48,45-

50.15); femur 77 (78,75-80,15) with 4 setae 42-54; genu 42 (43,40-44,15) with 4 setae
29-40, 2 a 25 each at 0.32 (0.31,0.29-0.33,15) and 0.50 (0.52,0.49-0.54,15); tibia 67
(67,65-69,15) with 5 setae 48-65, 2 4> 23 (23,22-25,15) and 25 (25,22-26,15) at 0.28
(0.27,0.25-0.29,15) and 0.83 (0.83,0.80-0.84,15), 1 k 4 (4,3-5,15) at 0.94 (0.95,0.920.96,15); tarsus 86 (87,84-88,15) with 13-14 setae 42-50, 1 w 29 (29,27-30,15) at 0.49
(0.49,0.47-0.51,15), 1 f3 1 (31,29-33,15) at 0.78 (0.77,0.75-0.80,15)(Fig. 64a).
Leg II 301 (302,298-310,15), coxal field 71 (72,70-74,15) with 2b 67 (67,6468.15) and 2c

63 (64,61-65,15); trochanter 46 (47,45-48,15) with 1 seta 52 (53,50-

54.15); femur 67 (68,65-69,15) with 3 setae 46-52; genu 38 (39,36-41,15) with 3 setae
38-44, 2 a 21 (22,20-25,15) and 15 (16,14-17,15) at 0.45 (0.46,0.42-0.47,15) and 0.35
(0.33,0.32-0.36,15) respectively; tibia 65 (66,62-67,15) with 5 setae 44-65, 2 0

19

(19,17-20,15) and 21 (21,20-24,15) at 0.23 (0.24,0.20-0.25,15) and 0.82 (0.83,0.800.85,15); tarsus 84 (85,82-86,15) with 13-14 setae 29-54, 1 w 17 (17,15-18,15) at 0.41
(0.40,0.39-0.43,15), no f(F ig . 64b).

114

Figs. 61, 62, 64a Allothrombium carum n. sp. (larva):
61a-b. dorsal and ventral idiosoma;
62a-b palpals;
64a. leg I trochanter to tarsus.
Scale lines for Figs. 61a-b, 62a, 64a each represent 100 ^m ; sclae line for Fig. 62b
represents 50 /*m.

Figs. 63, 64b-c. Allothrombium carum n. sp. (larva):
63, prodorsal sclerite;
64b-c, legs II-III femur to tarsus.
Scale lines each represent 100 fim.

115

116
Leg III 320 (322,315-333,15), coxal field 67 (67,65-69,15) with 3b 63 (64,61-65,15);
trochanter 54 (55,52-57,15) with 1 seta 50 (51,47-53,15); femur 54 (54,51-55,15) with
2 setae 57-69; genu 42 (43,40-44,15) with 3 setae 38-44, 2 a 23 (23,22-25,15) and 23
(22,20-24,15) at 0.31 (0.32,0.30-035,15) and 0.59 (0.60,0.57-0.63,15); tibia 77 (78,7579,15) with 5 setae 52-77, without <f>; tarsus 94 (95,92-97,15) with 11-13 setae 33-54
long, without w and f (Fig. 64c).
Deutonym ph:

unknown.

Adult females:
Some specimens were collected in the field from May to June of 1991 and 1992
and they laid eggs in the laboratory. Unfortunately, the slides were not good enough for
description. Additional specimens are needed to determine the relationship between the
larvae described above and other life stages of the species.
Discussion:
The genus Allothrombium Berlese, 1903, is a heterogeneous assemblage of about
50 species, of which 16 have been described from both the Palaearctic and Ethiopian
realms, 9 from the Australian, 3 from the Oriental, and 5 from the Neotropical region.
Four species are listed by Thor and Willmann (1941) for South America.
Ewing (1909,

1917) described two species from the United States: A.

missouriense (Ewing) 1909 from Missouri and A. pulvinum Ewing 1917 from Illinois.
Moss (1960) described A. lerouxi as a predator of small arthropods in Quebec
apple orchards. Davis (1961) reported a new species, A. mitchelli, as a predator on the
balsam woolly aphid, Chermes piceae Ratz. in North Carolina.

117
Most o f these species are known only from descriptions o f their nymph and adult
stages. Only a few species have described larvae (Feider,1951; Robaux et al., 1987;
Robaux, 1972).
Larvae o f A. carum differ from A. neapolitum in having larger AL, AW, PW,
SB and smaller SE, without ML; fewer femoral setae 4-3-2 instead o f 5-5-4; from A.
juliginosum in having larger AL, AW, PW, SB and without ML, fewer setae on femur,
genu, tibia and tarsus, Ge II and Ge III with 2 a respectively, T il, II with 2 <f>each
instead o f 1 for juliginosum, Ta III without 1 o> for the Michigan species; from A.
monspessulanum in having larger PW, AW, SB and without ML, fewer femoral and
tarsal setae. Details are listed in Table 9.
Etymology:
Allothrombium carum was repeatedly collected in both the Upper and Lower
Peninsulas o f Michigan during May 1990 and April 1991. It was found to be a predator
and an ectoparasite on insect pests and other small arthropods. The velvety appearance
o f adults attracted my attention at once when found on white pine bark. The latin word,
carum, meaning beloved, was used to describe this species that so much preferred pine
bark.
Distribution of Types:
Holotype larva and other 15 paratype larvae are in Department o f Zoology,
Michigan State University, East Lansing, MI.

118

Table 9. Distinguishing characters of Allothrombium carum n. sp. and three other close
species (larvae).

Species

Sclerite

Ge

AW PW SB AP AL PLSS

12 3
a

Ti
12 3
0

Ta
12 3
Cl)

A. neapolitum

75 81 45 36 39 62 79

2 22

222

I 1-

A. Juliginosum

*

2 1-

1 1-

11 1

A. monspessulanum

75 77 47 27 44 58 47

222

22 -

1 1-

A, carum

82 96 59 34 54 63 52

2 22

22-

1 1-

119
Subfamily Podothrombiinae Podothrombium fucum n.sp
Type series:
Holotype: 1 larva emerged on June 5, 1991 from eggs laid on April 28 by a
female collected from the forest floor two days earlier. Twenty paratype larvae were
obtained from the same egg clump. Ten additional larvae were obtained from eggs laid
during spring of 1991 by other females. Five paratype females and five paratype males
were collected in July of same year.
Larval description:
Color: in life red. Idiosoma 399 (388,367-412,30) long by 236 (242,228-257,30) wide.
Dorsal setae 53 (55,52-57,30), 46-52 in length; C l pair of setae on sclerite, ventral setae
31 (32,30-35,30) 38-42 long, 3a 52 (53,50-55,30) between coxal field III (Fig. 65a, b).
Pal pals: palpal genu 31 (31,29-33,30) with 1 seta 27-29, palpal tibia 23 (24,22-26,30),
palpal tibia claw entire 15 (16,14-17,30) with 2 nude setae 23-27, 1 short spine 8 (8,69.30); palpal tarsus 12 (12,10-14,30) with 4-5 barbed setae, 1 nude seta, 1 to and 3 f o r
2 f and 1 companion seta; palpal seta] formula: B-B-BNS-4BNto3f(2f-(- lc)(Fig. 66).
Prodorsal sclerite (Fig. 67): 144 (147,138-152,30) long by 105 (108,102-114,30) wide,
AM 63 (64,60-65,30), AL 59 (59,57-63,30), PL 63 (64,61-66,30), AW 19 (19,1722.30), MW 79 (77,75-80,30), PW 86 (87,85-89,30), AA 69 (70,68-73,30), ASB 19
(20,18-23,30), PSB 40 (41,39-44,30), ISD 77 (77,74-78,30), A-P 96 (97,94-98,30).
Eyes 2 + 2, 35 (35,33-36,30) long by 21 (22,20-23,30) wide anteriorly and 12
(12,10-14,30) wide posteriorly.
Legs (Fig. 68a-c): Leg I 386 (388,353-412,30), coxal field 90 (92,88-95,30) with la 54

120
(55,52-57,30) and lb 67 (67,64-69,30); trochanter 36 (37,34-39,30) with 1 seta 65
(66,63-67,30); femur 100 (102,95-110,30) with 5 setae 58-71; genu 67 (66,64-69,30)
with 4 setae 48-61, 2 a 27 each at 0.31 (0.32,0.30-0.35,30) and 0.60 (0.62,0.590.65,30), 1 k 8 (7,5-8,30) at 0.86 (0.85,0.84-0.88,30); tibia 77 (78,75-83,30) with 5-6
setae 50-61, 2

27 (27,25-29,30) and 25 (26,24-27,30) at 0.42 (0.43,0.40-0.45,30) and

0.90 (0.92,0.88-0.94,30), 1 k 8 (8,6-9,30); tarsus 105 (108,102-114,30) with 25-27 setae
35-48, 2 w 31 (32,29-34,30) and 35 (35,32-36,30) at 0.22 (0.23,0.20-0.25,30) and 0.62
(0.63,0.60-0.65,30), and 1 famulus respectively, lfh 38 (38,36-40,30) at 0.84
(0.85,0.82-0.86,30), 3 f 14-19 at dorsal 0.89-0.96 and 4 f at ventral region 0.60-0.65
(Fig. 68a).
Leg II 376 (372,361-393,30), coxal field 92 (93,90-96,30) with 2b 59 (59,5660.30); trochanter 40 (41,39-43,30) with 1 seta 65 (66,62-68,30); femur 90 (92,8994.30) with 4 setae 61-71; genu 58 (58,55-60,30) with 3 setae 54-56, 1 a 21 (22,1924.30) at 0.40 (0.41,0.39-0.43,30), 1 k 6 (7,5-8,30); tibia 77 (75,73-78,30) with 5 setae
48-61, 2 4>2l (22,20-24,30) and 17 (17,16-19,30) at 0.38 (0.37,0.35-0.40,30) and 0.90
(0.91,0.89-0.93,30);tarsus 111 (113,107-125,30)with 19-21 setae48-54, 1 «21 (21,2024.30) at 0.67 (0.68,0.65-0.72,30) and 1 famulus at 0.78-0.83 (Fig. 68b).
Leg III 424 (433,417-453,30), coxal field 81 (82,78-86,30) with 3b 61 (62,6064.30); trochanter 48 (48,46-50,30) with 1 seta 65 (66,62-67,30); femur 104 (107,101116.30) with 4 setae 52-71; genu 59 (61,58-64,30) with 3 setae 44-58, 1 a 23 (24,2025.30) at 0.58 (0.57,0.55-0.60,30); tibia 92 (94,90-98,30) with 5 setae 56-77, without
<£; tarsus 121 (124,118-135,30) with 18-21 setae 58-79, without « and f (Fig. 68c).

121
D eutonym ph:

Color in life yellow to brown. Idiosoma 834 (776,677-932,5) by 485

(521,466-623,5) wide. Palpal femur with 7-9 setae, 48 (46,42-53,5) long; palpal genu
67 (68,59-73,5) long with 12-14 setae; palpal tibia 72 (78,66-83,5) long with 3 spines
and 1 tibia claw; palpal tarsus 60 (63,60-73,5) long with 3-7 ca (Fig. 69). Prodorsal
sclerite 133 (142,128-163,5) long with 8 setae above SS setae, 5 setae between eyes and
SS setae (Fig. 70). Anal valvel with 8 setae total, 132 (142,130-164,5) long by 35
(38,31-54,5) wide (Fig. 71).
Adult female:
Color: in life brown. Idiosoma 1726 (1986,1677-1992,5) long by 987 (995,923-1012,5)
wide. Palpal tibia with 5 teeth at inner edge and rows of spinelike setae at dorsal edge,
3 claws at front, one at middle derived from pulvillus; palpal tarsus with to in rows (Fig.
72). Genital valves 368 (372,349-452,5) long with numerous setae; anal valves 118
(121,108-138,5) long with short setae around (Fig. 73a, b).
Prodorsal sclerite (Fig. 741: SE 136 (142,119-151,5), PW 102 (112,101-127,5), 11 setae
at each side. Eyes 2 + 2 , 121 (131,118-142,5) long by 105 (108,102-133,5) wide.
Legs:

Leg I 3299 (3326,3078-3645,5), coxal field 242 (238,212-265,5); trochanter 157

(159,144-173,5); basifemur 370 (383,355-396,5); telofemur 514 (522,507-566,5) with
11-12 N at 0.27-0.99; genu 587 (593,533-626,5) with 22-23 a at 0.08-0.96, 1 k 8-12 at
0.95-0.98; tibia 942 (938,918-975,5) with hundreds <f>in rows in all regions; tarsus 729
(735,716-767,5) with hundreds w in rows in all areas.
Leg II 2131 (2097,2018-2235,5), coxal field 298 (288,244-312,5), trochanter 148
(155,138-162,5); basifemur 261 (273,251-297,5); telofemur 320 (337,311-364,5) with

122

Figs. 65a, 66, 67. Podothrombium Jucum n. sp. (larva):
65a. dorsal idiosoma;
66, palpal tibia and tarsus;
67, prodorsal sclerite.
Scale lines for Figs. 65a, 67 each represent 100 m; scale line for Fig. 66 represents 50
fim.

123

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ZZs?
$ JZ

124

Figs. 65b, 68, 69, 70, 71. Podothrombium fucum (larva and deutonymph):
65b. ventral idiosoma (larva);
68a-c. legs I-III genu to tarsus (larva);
69. palpais (deutonymph);
70. prodorsal sclerite (deutonymph).
Scale lines for Figs. 65b, 68a-c, 72, 73 each represent 100 ^m.

125

71

126
3 N at 0.53-0.96; genu 364 (372,335-396,5) with 7-8 a at 0.05-0.90, 1 k 10-13 at 0.950.97; tibia 589 (595,547-613,5) with hundreds <t>\ tarsus 449 (433,416-466,5) with
hundreds co on the segment.
Leg III 2037 (2017,2006-2535,5), coxal field 261 (266,232-288,5); trochanter 159
(162,152-167,5); basifemur 263 (269,247-289,5); telofemur 311 (323,308-347,5) with
6-7 N at 0.49-0.94; genu 326 (332,318-347,5) with 11-12 a at 0.05-0.91; tibia 625
(637,615-665,5) with 29-30

at 0.06-0.94; tarsus 353 (355,332-366,5) with 19-21 a at

0.27-0.93.
Leg IV 2766 (2832,2557-2993,5), coxal field 244 (247,227-256,5); trochanter 246
(252,228-267,5); basifemur 320 (327,318-343,5); telofemur 407 (412,402-452,5) with
4-5 N at 0.34-0.90; genu 462 (477,433-488,5) with 8-9 a at 0.18-0.95; tibia 829
(843,817-866,5) with 23-24 <j>at 0.02-0.96; tarsus 503 (508,501-525,5) with 17-18 oj at
0.24-0.96.
Adult male:
Color: in fife brown. Idiosoma 1797 (1820,1563-1943,5) long by 915 (922,907-1012,5)
wide. Genital and anal valves with more setae than females.
Palpals: palpal femur 272 (288,265-294,5); palpal genu 140 (143,137-158,5); palpal tibia
167 (170,158-183,5), palpal tibia claw entire 54 (55,52-58,5) long, 4 spines next to the
claw, 5 spines at dorsal region; palpal tarsus 177 (180,167-192,5).
Prodorsal sclerite: 92 (95,90-98,5) long by 115(118,108-126,5) wide, SE 104(105,101116,5); SB 40 (41,39-44,5); posterior end slightly concave, 9 setae at each side of the
sclerite. Eyes 2 + 2, 121 (121,118-127,5) long by 102 (103,100-106,5) wide, AW 75

127
(76,73-78,5), PW 96 (97,93-99,5).
Legs: Leg I 3487 (3557,3178-3820,5), coxal field 297 (301,287-335,5); trochanter 190
(192,178-198,5); basifemur 445 (453,427-486,5); telofemur 525 (545,517-586,5) with
6-7 N 25-29 at 0.40-0.89; genu 608 (612,588-634,5) with 21-22 a 23-29 at 0.23-0.91;
tibia 986 (997,932-1033,30) with hundreds $ at all areas; tarsus 733 (747,718-788,30)
with hundreds w in rows.
Leg II 2254 (2473,2057-2783,30), coxal field 251 (262,236-288,30); trochanter
178 (188,164-198,30); basifemur 282 (297,255-312,30); telofemur 334 (342,302-378,30)
3-4 N 25-29 at 0.56-0.85; genu 378 (385,347-396,30) with 14-15 a 23-31 at 0.11-0.97;
tibia 589 (597,566-623,30) with hundreds <#>; tarsus 493 (505,488-547,30) with hundreds
os at 0.15-0.95.
Leg III 2173 (2285,2109-3321,30), coxal field 253 (262,233-274,30); trochanter
167 (172,147-183,30); basifemur 238 (253,218-277,30); telofemur 318 (332,302-363,30)
3 N 25-29 at 0.44-0.97; genu 349 (367,328-388,30) with 7-8 a 25-29 at 0.16-0.97; tibia
637 (647,618-683,30) with 24-25 <*>23-27 at 0.09-0.96; tarsus 464 (478,420-498,30) with
15-16 0)21-25 at 0.10-0.88.
Leg IV 2906 (2981,2235-3217,30), coxal field 341 (364,327-385,30); trochanter
247 (253,217-268,30); basifemur 249 (255,219-277,30); telofemur 462 (473,422-497,30)
with 5 N 25-29 at 0.33-0.96; genu 468 (483,455-522,30) 12-13 a 23-29 at 0.03-0.92;
tibia 949 (958,922-1012,30) with 26-30 <t> 23-29 at 0.04-0.95; tarsus 529 (544,511566,30) 10-11 a) 23-28 at 0.27-0.81.

128

Figs. 72-74. Podothrombium Jucum (adult female):
72. palpals;
73a. genital valves;
73b. anal valves;
74. prodorsal sclerite.
Scale lines for Figs. 72-74 each represent 100 /xm.

129

(Ml

W
73

SS

*

130
Discussion:
The generic description by Berlese (1910) from Italy was based on adults of the
type species Podothrombium bicolor (Hermann).
Since then 36 species have been described, mostly based on adults and
deutonymphs (Oudemans, 1910; Feider, 1968; Robaux, 1977, 1982). Among only five
of those species have adults been correlated with the larval forms (Robaux, 1982; Chang,
1989). Hosts of larvae were reported as aphids (Aphidae,Homoptera).
Podothrombium Jucum is close to P. paucisetarum in having few dorsal and ventral
setae and with respect to number of specialized genu setae. Significant differences which
distinguish the species from paucisetarum include narrow AW, ASB of sclerite (19:83,
19:116), length of sclerite (143:160), and number of specialized setae oi on tarsus (1-1-

0 : 2 - 1- 0 ) .
Etymology:
The species name is from a Latin word, jitcus, meaning red or purple.
D istribution of Types:
The holotype, 25 larval, 5 nymph and 5 female paratypes are in Department of
Zoology, Michigan State University, East Lansing, MI. One larval, nymph and female
paratypes will be deposited in each of the following institutions: Field Museum of
Natural History, Chicago, IL; Canadian National Collection, Ottawa, Ont; Shanghai
Institute of Entomology, Shanghai, PRC.

131
Family Calyptostomatidae

Calyptostoma nivalis n. sp.

Type series:
Holotype: 1 larva collected on May 24, 1988 from the forest floor, fifteen
paratypes also collected from the same site on May 14, 16,19, 1990 and May 23, 27,
1991. Only one deutonymph collected from a pastureland at Sagola, Michigan on May
15, 1984 by Nancy Sferra. Five adult females collected from the forest floor between
August and September of 1984.
Larval description:
Idiosoma (Fig. 75a, b, c):
Color: in life red, dorsal setae 256-264 in number, 38-42 anteriorly, 40-46
posteriorly, in 4 horizonal rows and 2 lateral zones; ventral idiosoma without setae, 5153 setae located after coxal field III, 36-42 anteriorly, 40-44 posteriorly. Eyes 2 + 2,
77 long by 54 wide, AW 48, AL 27, PW 50, PL 40.
Prodorsal sclerite (Fig.76):
SS 139 on dorsal protuberance, 52 long, and 48 wide; AW 33, MW 69, PW1 88,
PW2 96, AL 59, ML 33, PL1 46, PL2 40, SB 54, LX 4, A 21, B 17, C 27, L 121.
Palpal tibia claw small with 4 leaflike setae and 2 nude setae (Fig. 77).
Legs (Fig.78a-c): Leg I 585, coxal field 175 with 39 setae, 35-42 anteriorly, 48-50
posteriorly; trochanter 56 with 3 setae 40-63 in length; basifemur 117 with 23-25 setae,
42-52 anteriorly, 44-46 posteriorly; telofemur 50, 15 setae 44-52; genu 94 with 37-39
setae, 38-42 anteriorly, 36-46 posteriorly, 3 a 23 at 0.24, 27 at 0.42, 27 at 0.66, lk 10
at 0.90; tibia 107 with 52-56 setae, 42-48 anteriorly, 40-48 posteriorly, 5 <f>25 at 0.27,

132
25 at 0.38, 23 at 0.47, 23 at 0.60, and 27 at 0.78; tarsus 161 with 86-89 setae, 33-58
anteriorly, 44-48 posteriorly, 1 w 21 at 0.71, 2 fh 56 at 0.79, 40 at 0.83, 1 fp 25 at
0.93, and 4

oj

29 at 0.24, 31 at 0.43, 33 at 0.52, 31 at 0.63 (Fig. 78a).

Leg II 523, coxal field 159 with 43 setae, 40-48 anteriorly, 44-46 posteriorly;
trochanter 58 with 5 setae 52- 65; basifemur 111 with 17-19 setae, 42-44 anteriorly, 4458 posteriorly; telofemur 46 with 14-16 setae, 40-50 in length; genu 81 with 39-40 setae,
31-35 anteriorly, 21-36 posteriorly, 2 a 23 at 0.27, 27 at 0.51; tibia 88 with 36-38 setae,
31-40 anteriorly, 29-44 posteriorly, 2 0 27 at 0.21, 25 at 0.52; tarsus 139 with 68-72
setae, 44-54 anteriorly, 44-50 posteriorly, 1 « 29 at 0.58, 2 fh 58 at 0.57, 54 at 0.69
(Fig. 78b).
Leg III 591, coxal field 161 with 32 setae, 38-52 anteriorly, 46-56 posteriorly;
trochanter 67 with 3 setae 63-71; basifemur 127 with 13-15 setae, 52-58 anteriorly, 5059 posteriorly; telofemur 50 with 10-12 setae, 48-50 in length; genu 84 with 33-35 setae,
38-42 anteriorly, 40-46 posteriorly, 3 a 23 at 0.20, 27 at 0.42, and 25 at 0.60; tibia 115
with 36-38 setae, 36-48 anteriorly, 42-44 posteriorly, 1 0 25 at 0.58; tarsus 148 with 6769 setae, 33-56 anteriorly, 46-50 posteriorly, 1 fh 77 at 0.73, 1 fp 31 at 0.85 (Fig.78c).
Deutonymph:
Color: in life not recorded, presumed red. Body 830 long by 564 wide. Dorsal setae with
a big base 27-35 in length, ventral setae long and smooth 38-42. Anal valves without
setae (Fig. 79). Eyes 1 + 1, 58 long by 48 wide.
Palpals: palpal genu 111 with 2 long setae 59-63; palpal tibia 33 with 14-17 setae 25-38,
no prominent tibia claw observed, only 3 needlelike setae at the tip 13-17 in length;

133
palpal tarsus 58 with 31-33 setae 29-35 (Fig. 80).
Prodorsal sclerite: SS 102, SB 38, L 201, AW 27, PW 63 (Fig. 81).
Legs:

Leg I 564, coxal field 129, with smooth setae 40-48 in length; trochanter 52,

with a few setae 46-50; basifemur 130 with setae 38-48; telofemur 58 with setae 33-36;
genu 84 with setae 33-36, 3 a 21-23 at 0.23, 0.41 and 0.66 respectively, 1 k 6 at 0.93;
tibia 115 with setae 35-38, 5 <f>21-23 at 0.25, 0.50, 0.63, 0.86, 0.88 respectively; tarsus
125 with setae 36-38, 7-9 to 19-23 at 0.34-0.71, 4 £p 15-17 at 0.63-0.86, 2 claws entire
without pulvillums.
Leg II 506, coxal field 127 with setae 42-50; trochanter 59 with setae 52-54;
basifemur 127 with setae 48-50; telofemur 48 with setae 29-33; genu 65 with setae 2125, 2 a 19-21 at 0.23 and 0.32; tibia 88 with setae 31-33, 5 0 19-23 at 0.24-0.78; tarsus
119 with 8 a) 21-27 at 0.11-0.56, 1 fh 46 at 0.61, 5 long setae 41-44.
Leg III 503, coxal field 129 with setae 31-44; trochanter 48 with setae 40-56;
basifemur 127 with setae 42-48; telofemur 48 with setae 40-44; genu 69 with setae 2142, and 3 a 21-27 at 0.25, 0.83 and 0.86; tibia 92 with setae 31-35, 5 <f> 17-21 at
0.24,0.48 and 0.85; tarsus 119 with setae 40-42.
Leg IV 596, coxal field 142 with setae 42-50; trochanter 71 with setae 36-50;
basifemur 121 with setae 42-50; telofemur 58 with setae 40-44; genu 90 with setae 3536, 3 a 27-29 at 0.23-0.85; tibia 125 with setae 33-39, 5

23-27 at 0.24-0.82; tarsus

129 with setae 40-50.
Adult female:
Color: in life brown. Idiosoma ovoid, dorsal setae two types, 63-67 long for short ones,

134
and 77-90 long for long ones; ventral setae 90-100 in length (Fig. 82a, b).
Pal pals: palpal genu 386 (388,367-407,5); palpal tibia 67 (67,64-69,5), palpal tibia claw
10 (9,8-11,5); palpal tarsus 56 (57,54-58,5) with 6 long setae 71-102 in length (Fig. 83).
Prodorsal sclerite: with SS 82 (84,81-87,5) and SS base 77 long by 157 wide (Fig. 84).
Genital valves with numerous setae; anal valves with five setae at each side (Fig. 85a,
b).
Leg I 1588 (1672,1438-1726,5) long, coxal field 349 (352,318-366,5); trochanter
150 (152,138-157,5); basifemur 432 (445,417-466,5); telofemur 207 (212,201-224,5);
genu 316 (322,310-334,5) with 12-14 a 23-27 at 0.30-0.77; tibia 407 (418,404-427,5)
with 14-16 0 21-27 at 0.16-0.93; tarsus 508 (527,505-533,5) with 92-98 « 25-29 at 0.110.95, 1 fh 48-52 at 0.89-0.92.
Leg II 1272 (1321,1186-1457,5), coxal field 399 (404,388-432,5); trochanter 159
(162,153-172,5); basifemur 368 (377,358-397,5); telofemur 169 (175,148-182,5); genu
255 (264,237-288,5) with 3-5 a 19-23 at 0.29-0.37; tibia 290 (292,276-298,5) with 5-6
<f> 25-29 at 0.15-0.97; tarsus 399 (406,387-423,5) with 13-15 co 23-29 at 0.17-0.95,
without
Leg III 1747 (1824,1732-1988,5), coxal field 397 (405,388-415,5); trochanter 184
(188,168-197,5); basifemur 418 (427,412-466,5); telofemur 184 (188,177-192,5); genu
267 (273,255-287,5) with 3 a 19-23 at 0.24-0.77; tibia 299 (307,287-317,5) with 5-6 4>
23-27 at 0.27-0.77; tarsus 395 (404,388-412,5) 2 a) 17-19 at 0.67-0.71, without
Leg IV 2135 (2247,2108-2749,5), coxal field 416 (423,409-433,5); trochanter 265
(269,255-273,5); basifemur 449 (454,432-475,5); telofemur 230 (241,212-267,5); genu

135
328 (331,315-354,5) without <r; tibia 372 (375,366-383,5) with 3-4 <j>19-23 at 0.21-0.53;
tarsus 491 (488,475-507,5) with 2 to 17-19 at 0.70-0.73.
Discussion;
The genus was erected by Cambridge in 1875. A few species described in Europe
were placed in this genus (Miller, 1776; Hermann, 1804). Their special morphological
features easily place them in the family Calyptostomatidae, which is characterized by
larval coxal fields possessing multiple setae. The new species represents a first generic
record for North America.
Etymology:
The Latin species name, nivalis, refers to the prolonged snowy winters in
Michigan’s Upper Peninsula.
Distribution of Types:
The holotype and paratypes are in Department of Zoology, Michigan State
University, East Lansing, MI.

136

Figs. 75-78a. Calyptostoma nivalis n. sp. (larva):
75a-b, dorsal and ventral idiosoma,
75c, dorsal and ventral setae;
76, dorsal sensary setae;
77, palpals;
78a, leg I genu to tarsus.
Scale lines for Figs. 75a-b, 76, 78a each represent 100 ^m ; scale line for Figs. 75c, 77
represents 50 pm.

137

138

Figs. 78b-c, 79-82 , 84-85. Calyptostoma nivalis n. sp. (larva, deutonymph and
female):
78b-c, legs II-III (larva);
79, anal valves (deutonymph);
80, gnathosoma (deutonymph);
81, prodorsal sclerite (deutonymph);
82a-b, dorsal and ventral setae (female);
84, prodorsal sclerite (female).
Scale lines for Figs. 78b-c, 79, 80 81, 84, 85 each represent 100 /xm; scale line for Fig.
82a-b represents 50 nm.

140

Fig. 83. Calyptostoma nivalis n. sp. (female): palpals.
Scale line represent 100 fim.

1A1

142
Family Eutrombidiidae

Hexathrombium bicomarum n. sp.

Type series:
Holotype: 1 larva collected on 15 May, 1991 from forest litter. Fifteen larval
paratypes collected at the same location in 1988 and 1991. Host unknown. Nymphs and
adults are also unknown.
Larval description:
Color: in life yellow to light brown. Idiosoma ovoid, 272 (285,266-331,15) long by 148
(157,142-170,15) wide. One pair of eyes set on each side of prodorsum, anterior eye 10
(9,8-11,15) long and 12 (11,10-13,15) wide, posterior eye 13 (14,12-15,15) long and 12
(12,10-14,15) wide (Fig. 86a, b). Gnathosoma 188 (192,174-216,5) long with 1 palpal
genu seta, 3 palpal tarsus setae and 1 f without tibia claw (Fig. 87a, b).
Dorsal setae (Fig. 88): Dorsal setae 19, 56-63 in length anteriorly, setae C l on sclerite
(scutellum) 63 (64,61-65,15) long; scutellum 15 (16,13-17,15) long; PD 38 (39,3740.15); SBa 75 (76,73-78,15); AW 200 (201,198-208,15); PW 180 (182,178-187,15);
ABD 65 (66,63-68,15).
D1 pair o f setae on sclerite 65 (67,62-69,15); scutellum 14 (14,12-16,15); PD 25
(26,22-27,15); SBa 65 (67,63-69,15); ABD 42 (44,41-16,15); AW 150 (151,146156.15); PW 138 (140,137-143,15); L 38 (39,37-40,15).
E l pair o f setae on sclerite 73 (74,70-78,15); scutellum 13 (14,12-16,15); PD 27
(27,24-28,15); SBa 67 (68,65-72,15); ABD 25 (25,22-27,15); AW 117 (118,113122.15); PW 101 (104,100-108,15);L 40 (42,39-45,15).
HI setae on sclerite 75 (76,72-78,15) in length, H2 setae on seperate sclerite 76

143
(77,74-79,15); ABD 13 (14,13-16,15); SBa 29 (29,27-30,15); AW 56 (57,54-60,15); PW
40 (42,39-44,15).
Ventral setae (Fig. 89): with la of barbed intercoxal setae between coxal field leg I, 25
(26,23-27,15), and 1 pair (3a) between coxal field leg III, 29 (29,27-32,15); after coxal
field leg III, 18B setae in length from 33-35 anteriorly and 40-46 posteriorly, setae lb,2b
and 3b in length from 12, 12 and 10 are modified (Fig. 87a,b). 1 preanal tuburical seta.
Prodorsal sclerite: AM 36 (37,33-38,15); SS 77 (77,73-78,15); AL 79 (79,74-82,15);
PL 58 (58,53-60,15); L 165 (170,156-179,15); W 194 (198,180-210,15); AW 140
(147,138-156,15); PW 190 (193,185-198,15); AAS 69 (71,67-74,15); LX 77 (76,7378.15); PPS 27 (27,24-29,15); SBa 82 (83,80-87,15); SBp 135 (139,134-142,15); ISD
101 (105,100-110,15); ASBa 3 (3,2-4,15); PSD 33 (34,30-36,15).
Legs (Fig. 90a, b, c): Length: leg I from trochanter to pretarsus 200 (201,193-208,15);
leg II 159 (160,157-164,15); leg III 146 (148,142-152,15).
Leg I: coxal field with 1 modified, bifurcated seta and 1 nude seta; trochanter
with IB 25 (26,22-28,15); femur with 3B 27-36, 1 N 34 (36,32-38,15) at 0.16
(0.16,0.14-0.18,15); genu with 4B 35-36, 1 a 25 (26,23-28,15) and 1 k 4 at 0.92; tibia
with 6B 36-38, 2 0 29 (30,27-34,15) at 0.50 (0.50,0.48-0.53,15) and 31 (32,28-34,15)
at 0.89 (0.88,0.85-0.92,15) and lk 4-6 at 0.91-0.93; tarsus with 16B 23-35, 1 u> 33
(34,31-36,15) at 0.47 (0.48,0.45-0.50,15), 1 famulus 23 (24,22-26,15) at 0.94
(0.94,0.92-0.95,15) (Fig. 90a).
Leg II: coxal field with 1 modified, bifurcated seta; trochanter with IB 27 (27,2529.15); femur with 4B 33-48, 1 N 31 (32,29-33,15) at 0.20 (0.22,0.18-0.25,15); genu

144
with 2B 27-36, 1 a 25 (26,23-26,15); tibia with 5B 33-36, 2 0 21 (21,20-22,15) at 0.40
(0.42,0.40-0.45,15) and 21 (22,19-23,15)at 0.71 (0.68-0.73,15); tarsus with 15B 23-31,
1 w 21 (21,20-23,15) at 0.37 (0.37,0.35-0.38,15), and 1 fumulus (Fig. 90b).
Leg III: coxal field with 1 modified, bifurcated seta, smaller than setae on legs I
and II; trochanter with IB 31 (32,30-34,15); femur with 3B 31-39, 1 N 29 (29,28-32,15)
at 0.13 (0.14,0.12-0.15,15); genu with 2B 37-44 and 1 a 29 (29,27-33,15); tibia with 4B
33-40?; tarsus bifurcate with 8-9B 29-44, pretarsus with only emporium and modifided
claw, 1 f 33 (33,30-35,15) at 0.71 (0.72,0.69-0.74,15), 1 lobe seta 48 (47,45-49,15) at
0.86 (0.85,0.84-0.87,15)(Fig. 90c).
D eutonym ph an d adult: unknown.
Etymology:
The species name is a Latin word, bi-, comarum, meaning two hairs on dorsal
sclerite.
Discussion:
This is the second species of the genus ever collected in the world. The first was
reported from Brussels by Cooreman (1949) as a new species and a new genus,
Hexathrombium spatuliferum. Hexathrombium bicomarum differs in having 2 dorsal setae
on a sclerite at the posterior pole of the idiosoma.
D istribution o f Types:
The holotype and paratypes are in Department of Zoology, Michigan State
University, East Lansing, MI.

145

Figs. 86-89. Hexathrombium bicomarum n. sp. (larva):
86a-b, dorsal and ventral idiosoma;
86d, dorsal and ventral setae;

86c, eyes;
86e, anal pore.

87a-b, gnathosoma and palpal s;
88, dorsal sclerites and setae;
89, ventral coxal fields I-III.
Scale lines for Figs. 86a-b, 87a, 88, 89 each represent 100 /am; scale lines for Figs. 86de, 87b each represent 50 /im; scale line for Fig. 86c represents 40 /im.

146

147

Fig. 90a-c. Hexathrombidium bicomarum n. sp. (larva): legs I-III, scale line for legs
represents 100 pm, scale line for tarsus I, tibia III and tarsus III represent 50 pm.

90

b

90

PART II: ECOBIOLOGICAL STUDIES

149

150

PART II. ECOBIOLOGICAL STUDIES
1. MATERIALS AND METHODS:
1. 1. REARING MITES FROM ADULTS:
Adults were collected from the forest floor, bushes and trees from May to
August. Large body size often identified gravid females. Sometimes Project ELF data
aided in determining when gravid females were likely to be present. Culture jars and
other containers used for adult rearing, maintenance of humidity, laboratory conditions
and food sources are described in Part I.
Only one adult mite was placed in a given vial, which was labeled with locality
and date. After eggs had been laid, the female was transferred to a new culture jar to
prevent cannibalism. Eggs were counted and labeled appropriately, and were checked
daily to observe their developmental rate. Mold growing in the cultures was removed.
When females died, they were preserved and labeled.
Once the larvae emerged, some were preserved in alcohol and labeled with
information regarding the parent. Others were introduced to new containers with insect
hosts collected in the field, and placed in an incubator at 14 ± 1.5 °C, and an 8:16 hour
(light:dark) cycle.
Containers with larvae and potential hosts were checked every day, and the
number o f parasitized hosts and the number of parasites per host were counted. Hosts
with mite larvae were isolated. When engorged larvae were found in the container, they
were again transferred to a new culture vial. Once quiescent protonymphs appeared, the
specimens were observed every other day until the deutonymphs emerged. The same food

151
supplied to adults was also used for nymphs. Some deutonymphs were preserved in
alcohol and labeled, others were reared to adulthood.
1. 2. REARING MITES FROM HOSTS:
From spring to fall, hosts with attached larval mites were collected in the field.
In early July, moths with larval Leptus parasites were collected by means o f a light trap.
Each live host was placed in a labeled container and supplied with appropriate foods (e.
g ., honey solution for moths, grass for grasshoppers).
Once the larvae dropped off the hosts, they were transferred to moist culture
vials. Sometimes different larval species were found on a single host. If possible, they
were moved to individual vials and labeled according to host, locality, date and
attachment site. Subsequent rearing procedures were as described above.
In fall, when engorged larvae were obtained, they were moved to a cold, dark
room at -4 + 1.5 °C once they entered diapause. Duration of the diapause stage was
recorded separately for each individual. When deutonymphs entered diapause, they were
also moved to the same cold room for the winter, and duration of diapause larvae or
deutonymph stage was recorded for every individual.
1. 3. FIELD OBSERVATIONS OF DIEL ACTIVITY:
On July 13 and 14 o f 1990, a 24-hour field survey was performed to record diel
activity o f the species in the field by means o f 10 pitfall traps which were activated at
1:00 pm, and emptied and replaced every 4 hours from 5:00 pm to 5:00 pm on the
following day.

152
I. 4. HOST PREFERENCE STUDIES:
A. Field collection:
Pitfall traps, litter and soil core samples were used to collect many specimens in
the field. In addition, a sweepnet was used from spring to fall to collect deutonymphs,
adults and hosts parasitized by larvae. For moths and other night-active hosts, a light trap
was used on warm summer nights, usually from late June to mid-August (for details see
Part I). Hand-collecting yielded many adults during spring and summer, and was also
useful for obtaining larger hosts such as grasshoppers.
Collected insects were checked and the number and species of hosts as well as the
number o f mites per host were recorded. Attachment sites on the hosts were also
recorded as part of host preference information. Field collections were made every other
day during the summer for three years.
B. Laboratory observations:
Food for mites and hosts, rearing containers and other laboratory procedures are
described in Part I. When larvae hatched from an egg mass, they were transferred to
glass jars as described above (see section 1.1.), and a given insect or other host species
was introduced (usually 50 host individuals were collected in the field). One day later,
the number o f parasitized hosts and the number of mites per host was counted. The jars
were checked frequently until there were no more larvae available. Sites of attachment
on hosts were also recorded to provide detailed information on mite behavior.

153
1. 5. R ESPO N SE O F T H R EE SPECIES TO R ELA TIV E H U M ID ITY :
Following the work o f Snider (1968) a series o f glycerin solutions was used to
create relative humidities from 0 % to 100 % in 10 % increments. Small, tightly-closed
plastic jars, with a fine screen separating the glycerin solution from the mites, were used
as containers for the experiment. Ten replicates (one adult per jar) were set up at each
humidity level. The number o f surviving mites was counted every 3 hours until
termination o f the experiment at 72 hours. At very low humidities (0-30 %), the jars
were checked more frequently, sometimes every half hour. Collembola and their eggs
served as food.

2. RESU LTS:
2. 1. L IF E H ISTO R IES O F 11 SPECIES:
Generally, life history o f velvet mites includes one parasitic larva stage, two freeliving stages, i. e. deutonymph and adult are active as predators; and three quiescent
stages: prelarva or egg stage; prenymph or engorged larva stage and tritonymph stage,
which is from egg to larva to protonymph to deutonymph to tritonymph, and then to
adult.
Based on my own observations and on data obtained from Project ELF, the life
histories o f 11 species fell into three distinct groups (Type I, II and III) (Table 10).
Type I: these species overwinter as tritonymphs, become adults and oviposit in
the spring. Larvae search for and parasitize hosts in early- to mid- summer. After
engorgement, larvae develop to protonymphs and active deutonymphs, and their

154
tritonymphs enter diapause in late fall and overwinter.
Type II: eggs overwinter (many females are gravid in late fall), larvae appear in
April through May of the following year. Predatory deutonymphs emerge during
summer, and gradually mature to tritonymphs and finally to adults which mate and
reproduce before the onset of winter.
Type III:

this group is represented mainly by a small fraction of the T.

auroraense population. These individuals deviate from the Type I life cycle in
developmental rates. In the laboratory, a single egg mass may yield larvae over a period
of up to one month. In the field, larvae may hatch as late as August or September, and
spend the winter as engorged larvae or protonymphs. Deutonymphs appear in next spring
and become adults in summer of the following year.

155
Table 10. Types o f life histories of 11 velvet mite species: seasonal appearance
of life stages. LV = larvae, PN = Protonymph, DN = Deutonymph,
TN = tritonymph, Ad = adult.

Type

Spring

Summer

Fall

Winter

I

Ad

LV & PN

DN

TN

II

LV

DN & TN

Ad

Eggs

Ad & eggs

LV

PN

III

DN & T N

Type I and II life cycles are the most common; Type III may be a variation of
Type I induced by variable developmental rates and by year-specific climatic conditions.
A more detailed seasonal breakdown of developmental patterns in the field is provided
in Tables 11 to 13.

Table 11. Type I life history: breakdown into seasonal events. Abbreviations as in Table

10.
Season

April

Stage

Ad

May
eggs

June
LV

July

August

LV/PN

DN

Sept/Oct.

Winter

DN/TN

TN

156
The species exhibiting a Type I life cycle are L. sylvestratilis, L. solitarius, E.
michiganensis, E. septemsetalis, E. locustarum, B. nonasum, and T. auroraense.

T able 12. Type II life history: breakdown into seasonal events.
GF = gravid females, other abbreviations as in Table 10.

Season

April

May

June

July

Stage

LV

PN

DN

TN

August
Ad

Sept/Oct.

Winter

GF/eggs

eggs

Species in this group are A. welbourni, P. jucum , A. carum and C. cunarum.

Table 13. Type III life history: breakdown into seasonal events. Abbreviations
as in Table 10.

Season

April

May

June

July

August

Sept.

Winter

Stage

DN

TN

Ad

eggs

LV

PN

PN

Part o f the population o f T. auroraense belongs to the Type III group.

157
Two species which were commonly obtained from pit-traps during Project ELF
(A. welbourni and T. auroraense) illustrate the year-to-year constancy of the above life
histories (Table 14). Type I is exemplified by T. auroraense, with larvae appearing in
summer and adults in spring; Type II is illustrated by A. welbourni, with larvae active
in spring and adults appearing in mid-summer (Table 14).

158

Table 14. Seasonal appearance of life stages of two dominant species in 3 years, based
on pit-trapping data of Project ELF. Data excerpted from Snider and Snider (1985, 1986,
1987).

species

year

Dates

and

LV
range

A. welbourni

T. auroraense

peak

range

DN
peaks

Stages
Ad
range

peaks

7/16-9/17

7/23-8/12

6/3-7/15 6/3,9,17

6/24-9/9

7/22,29

6/9-7/13 6/9,7/10

7/7-9/15

7/13.28

5/7-7Z2

5/7,13,21

.

5/5-6/9

5/5,13,20

-

5/6-6/23

5/6,12,27

85

5/7-28

5/7,13,21

6/4-7/1

86

5/5-27

5/5,13,20

87

5/6-21

5/6,12

85

7/16-8/13 7/23,30

86

7/8-S/5

7/22

87

6/23-7/28 7/7

6/17,25

peaks = > 85% o f all individuals trapped occurred on the dates listed; range = time
period over which a given stage was commonly trapped; - = no data available.

159
2. 2. H O S T AND PREY SELECTIO N :
Based on field collections in 1990 and 1991, larvae of L. solitarius parasitized
moths and grasshoppers at approximately equal rates during July. Rates of parasitization
in both host groups declined in August (presumbly because larval densities were lower)
(Table 15).
The parasitization rates o f larvae on these two major hosts did not vary much
from year to year. For example, the parasitization rate on moths in July, 1990 was 7.9% ,
and 7.5 % for the same time in 1991. In grasshoppers, the rate was 6.8 % in July, 1990
and 7.7 % in 1991. In Table 14, "others" refers to other hosts, such as leafhoppers, crab
spiders, flies, crane flies, beetles and other arthropods.
Hosts of T. auroraense included 16 insect species in 1990, including craneflies,
houseflies, deerflies, mosquitoes and other insects in early July, 1990. Grasshoppers
rarely carried mites at that time. As the density of grasshoppers gradually increased from
late July to August, more and more larvae of T. auroraense paratisized grasshoppers
instead o f other insects (Table 16).
Hosts o f six other mite species included mainly aphids, leafhoppers and other
small insects. These mites are A. welbourni, A. carum, B. nonasum, C. cunarum, E.
michiganensis, and P. fitcum . Hosts of E. locustarum consisted exclusively of three
species o f grasshoppers in the genus Melanoplus (Table 17).

160
Table 15. Summary data of host records of L. solitarius larvae in 1990 and 1991; data
are given as number o f hosts carrying larvae/total number of hosts examined.

Date/Hosts
N

1990

others

Grasshoppers

Moths
%

N

%

N

%

July
10-18

21/191

11.0

3/51

5.8

0/44

0.0

24-30

6/149

4.0

5/65

7.6

1/36

2.8

July total

27/340

7.9

8/116

6.8

1/80

1.3

1/100

1.0

3/58

5.2

1/26

3.8

0/43

0.0

2/210

0.9

0/39

0.0

1/143

0.7

5/268

1.8

1/65

1.5

26/503

5.2

13/384

3.4

2/145

1.4

5-12

23/294

7.8

3/64

4.7

0/107

0.0

17-25

14/198

7.0

6/52

11.5

2/95

2.1

July total

37/492

7.5

9/116

7.7

2/202

0.9

2-12

6/98

6.1

2/78

2.5

3/59

5.0

18-30

0/39

0.0

1/131

0.7

2/125

1.6

6/137

4.4

3/209

1.4

5/184

2.7

43/629

6.8

12/325

3.7

5/184

2.7

August
1-13
21-30
August total
Total
1991
July

August

August total
Total

161
T able 16. Host usage by T. auroraense in July and August, 1990: data are given as
number o f hosts carrying larvae/total number of hosts examined.

Host/Date

July subtotal

August subtotal

Total

%

N

%

Tipula sp.

5/53

9.4

0/16

0.0

5/69

7.2

Protoplasa fitchii

2/46

4.3

0/22

0.0

2/68

2.9

M u sea sp.

9.3

8.2
6.9

1/32

3.1

0.0
2.7

9/109
4/58

Chrysops univittatus

2/34
0/21
1/36

5.8

Herme t i a illuceua

7/75
2/37

2/68

2.9

Aeries stimulaus

2/96

2.0

0/42

0.0

2/138

1.4

A. sollicltaus

1/56

1.7

0/25

0.0

1/81

1.2

punctlpennis

2/74

2.7

0/36

0.0

2/110

1.8

Sarcophaga sp.

1/35

2.8

1/13

7.6

2/48

4.1

1/17

5.8

0/10

0.0

1/27

3 .7

1/17

5.8

0

0.0

1/17

5.8

2/49

4.1

1/48

2.0

3/97

3.0

3/55

5.4

0/20

0.0

3/75

4.0

5.4

N

%

N

Anopheles

ApAirioiestes
m eridionalis
Chrysopa s p .
Poecilocapsus
llneatus
Ly g u s lineolaris
M e l anoplus
differential is
M. confusus
M. bivittatus

27/90

30.0

36/144

25.0

63/234

26.9

16/56
8/30

28.6
26.7

20/104
16/68

19.2
23. 5

36/160
24/98

22.5
24.4

162
Table 17. Host and prey preferences of seven species of velvet mites: data are given in
numbers of hosts with larvae attached/total number of hosts collected; (N) = nymphs of
hosts.
Hites
Allothrombium
carusm

Abrolophus
welbourni

Charletonia
cunarum

Hosts

N

%

23/427
19/409
11/362

5.3
4.6
3.0

Chaetosiphon tetrarhodum

8/176

4.5

Rhopalosiphum ribis ?

4/119

3.3

Macrosiphum pisi

3/112

2.6

Graphocephala coccinea(N)

5/133

3.7

Scaphoideus
luteolus fN)

5/143

3.4

Paraphlepsius
irzroratus (K)

7/147

4.7

Aphis rumicis
A. pomi

4/121
5/100

3.3
5.0

27/366

7.3

Lachnus confinis

15/261

5.9

Maerosiphum pisi

9/222

4.0

Aphis sambuci
A. rumicis
A. pomi

Erythraeus
mlchiganensis A. rumicis

Eutrombidium
locustarum

Melanoplus
differentialis

43/79

54.0

M. confusus

22/55

40.0

M.bivittatus

16/40

40.0

8/40
10/79
5/55

20.0
12.6
9.1

Leptua
sylvestratilia
M. bivittatus
M. differentialis
M. confusus
Podothrombium
fucum

Aphis rumicis

7/218

3.2

A . forbesi

4/214

1.8

Sipha avenae

6/213

2.8

163
Differences in the number of larvae carried by a single host seemed to be
correlated to its size. For instance, a grasshopper might have 12-25 mites attached to it,
while leafhoppers often had only one mite parasite. Body size, physiological state, and
behavior of hosts are probably interactive in the final outcome of parasitization rate.
In the laboratory, host preference tests were carried out using 11 types of hosts
and six species of mites, larvae of which were available in relatively large numbers
(Table 18).
Parasitization ratios in the laboratory were probably higher than what they might
be in the field since hosts could not avoid attacks from larvae in a closed container. For
instance, in two sets of 150 grasshoppers introduced to L. sylvestratilis and E.
locustarum, 146 and 148 of them had larvae attached respectively.
As shown in Tables 16 and 18, Tauroraense used 16 host species in the field
and 19 species in the laboratory, but larvae attached to dragonflies, some spiders and
some leafbeetles never became engorged. This may indicate that these were occasional
hosts and not real hosts in the field. Field records of hosts for T. auroraense differed
from another report from New York state, where the same species mainly parasitized
weevils (Hypera postica Gyll.) in alfalfa fields (V. Grandjean et al., 1977).
On the other hand, E. locustarum and L. sylvestratilis only parasitized
grasshoppers both in the field and in the laboratory. Although larvae of L. solitarius
would use grasshoppers and moths in the laboratory, field records on grasshoppers were
rare. Erythraeus michiganensis and P. fucum each could use six host species in the
laboratory. However, in the field, larvae of E. michiganensis attached to both leafhoppers

164
and aphids, and P. JUcum mainly parasitized leafhoppers.

Table 18. Host acceptance by six mite species under laboratory conditions: data are given in number of hosts with mites
attached (of 150 host individuals introduced), number of species in parentheses.
Host/Mite

T. auroraense

L. sylvestratilis

L. solitarius E.locustarum P.fucum

0

142

0

grasshoppers(3)

142

146

146

148

flies (3)

118

0
0

6

0
0
0
0

moths (7)

craneflies

0

(2)

88

leafhoppers (3)

31

aphids (3)

0

leafbeetle (2)
groundbeetle (2)

41
0

leafmites (2)

16

spiders

12

(3)

dragonflies (3)

0
0

E. michiganensis

0
0

0

0
0

0
0
0
0

0

0

44

74

6

0

5

31

0

0

0

0

0

0

0
0

0
0

0
0

2

33

33

33

8

0

0

27

Total host species offered
33

33

33

Total host species accepted
19

13

166
Based on all available field and laboratory observations, a list of the main hosts
used by velvet mites in the study area is presented below (Table 19).

Table 19. A list of host records for velvet mites in Michigan deciduous forest.
Mite species
Allothrombium carium

Host species
Aphis sambuci, A. rumicis, A. pom i,
Chaetosiphon tetrarhodum,
Rhopalosiphum ribis, Macrosiphum pisi

Eutrombidium locustarum

Melanoplus differentialis,
M. confusus, M. bivittatus

Podothrombium jucium
Trombidium auroraense

Aphis rumicis, A. forbesi, Sipha avenae
Melanoplus differentialis, M. confusus,
M.

bivittatus,

Musca

sp.,

Tipula

sp.,

Hermetia illuceus, Lygus lineolaris, Aedes stimulus,
Anopheles punctipennis,
Abrolophus

welboumi

Graphocephala

coccinea,

Scaphoideus

luteolus,

Paraphlepsius irroratus
Charletonia cularia

Aphis pomi, A. rumicis

Erythraeus michiganensis

A. rumicis, Lachnus confinis, Macrosiphum pisi.

Leptus sylvestratilis

Melanoplus bivittatus, M. confusus, M. differentialis.

L. solitarius

Crambus vitellus, Coryphista meadi altantic,
Dioryctria abietella, Euphyia intermedia,

167
L. solitarius

Melanoplus differentials, M. conjusus, M, bivittatus,
Musca sp, , Miltogramma sp.

A possible relationship between host specificity and maturation was observed in
the case o f T. auroraense. Engorged larvae of the species were obtained from two types
o f host (leafbugs and grasshoppers) in 1989, reared to deutonymphs, and overwintered
in the laboratory. Resulting data are given in Table 20.

Table 20. Survival of deutonymphs and size 0*m) of emerging adults of Trombidium
auroraense overwintered in the laboratory (4 + 1 .5°C , R H = 90% , L ight= 0).

Host
o f larvae
leafbugs
grasshoppers

Fall 89
N deutonymphs
107
89

Spring 90
N adults (mean length x width)
12 (816 x 618)
40 (1322 x 1144)

More deutonymphs stemming from larvae fed on grasshoppers matured to
adulthood than those fed on leafbugs. The number o f larvae reaching the adult stage as
well as the body size of individuals were both smaller than those fed on grasshoppers,
possibly due to nutritional reasons. This observation could be related to higher
parasitization ratios on grasshoppers observed in the field, indicating a true "preference".

168
An attempt was made to explore the relationships between parasitic mites sharing
the same host resource from both laboratory and field observation. Mid-June to late July,
larvae of L. sylvestratilis, T. auroraense and E. locustarum were found mainly on
grasshoppers in wooded grasslands, at roadsides and in other open areas in the forest.
Attachment sites of L. sylvestratilis were located almost everywhere except on the wings
(Table 21). Among a total of 106 L. sylvestratilis larvae, 66 were attached to legs, 20
were found on the antennae, six on mouthparts and nine on the host body. However, the
larvae of E. locustarum and T. auroraense were found exclusively underneath the wings
of the hosts.
Unlike L. sylvestratilis, L. solitarius larvae preferred moths as their major hosts,
when the larval density of Trombidium reached a peak in early to mid-July. Although
larvae were also found on grasshoppers, they were never attached to the wings. Other
insects and arthropods, such as crab spiders and scorpionflies, also served as hosts. In
laboratory rearing, however, L. solitarius accepted a wider range of host species than L.
sylvestratilis (in addition to the moths preferred in the field).

Table 21. Attachment sites of larval L. sylvestratilis on grasshoppers: values represent the number of larvae found on a given
anatomical area of the host.
Host

6 /1 6

6/21

6 /2 3

2
2
19
4
1
1

1
2
5
1
1

1
-

-

1
1

-

4

1
1

2

1

-

-

-

1

1
1

2
-

2
1
1

Date 6 /1 3

7 /5

7 /9

7 /1 0

-

1

-

-

-

1
1
1

1

1
1

2
1
1

-

-

7 /1 3

7 /1 8

7 /2 1 7 /2 6

Total

Melanoplus
differentialis

legs/tibia
tarsus
femur
antenna
cervex
labial pals
abdominal
segments
cerci
wings

1
2
-

2

-

1

-

-

1
1

1
1

-

-

1

5
9
31
10
3
3

-

-

3
1

1

10
2
9
10

““

*■

—

—

-

-

-

-

-

-

1

-

1

-

-

1

1

1

-

-

•

—

—

—

•

—

-

-

-

1

-

-

1

M. confusus

legs/tibia
tarsus
femur
antenna
cervex
labial pals
abdominal
segments
cerci
wings
Total

1
2
3
-

2

1

1
1

-

—

43

1

2

1

3

3

—

—

—

—

—

—

—

—

2

—

—

17

10

11

6

5

3

2

2

4

3

106

1

2
—

170
Mechanisms of co-existence for species sharing grasshopper hosts and examples
are summarized below.
1. Location of attachment on insect hosts:
a. Eutrombidium locustarum attached to grasshopper wings;
b. Leptus sylvestratilis attached to grasshopper antennae,
mouthparts and legs.
2. Wider range of host species when larval densities are at a
maximum:
a. Trombidium auroraense was found to use 16 host species,
grasshoppers,leafhoppers, flies, craneflies and leafbeetles among them;
b. Leptus solitarius was found to use seven moth species, two
scorpionflies, one opilionid and one crab spider species.
3. Different seasonal occurrence of larvae which tend to use the
same host:
a. E. locustarum and L. sylvestratilis were active in June;
b. T. auroraense larvae were active in July and August.

2. 3. RESPONSES OF THREE COMMON SPECIES TO RELATIVE HUMIDITY:
At 80% relative humidity (RH) and above, all three species (A. welbourni, L,
sylvestratilis and T. auroraense) could survive quite well since the mortality rate of adults
after 72 hours varied little between 80% and 100% RH. At 0% RH, survival rate of all
species was low, but differences of tolerance to 0% were observed (Figs. 91-93). Among

171
A. welbourni, 50% were dead after 3 hours, as opposed to 5 and 14 hours for L.
sylvestratilis and T. auroraense respectively. At 10, 20 and 30% RH, A. welbourni
experienced 100% mortality after 15, 30 and 36 hours respectively. Survival over the
entire 72 hour period was observed only in L. sylvestratilis (one individual at 30% RH)
and T, auroraense (two and three individuals at 20% and 30% RH respectively).
Survival rates of adult velvet mites at various relative humidities showed that
Abrolophus welbourni was very sensitive to low humidity; and that, among the three
species, T. auroraense tolerated low humidity better than the others.

172

T. auroraense
Survival rate (%)

— 100 %

+ 90%
+ 80%

*70%
60

+ 60%

40

+ 50%
+ 40%
+ 30%

20

♦ 20%
+ 10%

0

10

20

30

40

SO

60

70

+ 0%

Time (Hours)

Fig. 91. Survival rate (%) of T. auroraense at different relative humidities.

L.

sylvestratilis

survival rate (%)
*

100*

100 %

+ 90%
+ 80%

80

+ 70%
60

+ 60%

40

+ 50%
+ 40%
+ 30%

V

♦ 20 %
+

20

30

40

50

60

70

10%

+ 0%

Tme (hours)

Fig. 92. Survival rate (%) of L. sylvestratilis at different relative humidities.

173

A. welbourni
Survival rate (%)

—

10<

100 %

-+- 90 %
* 80 %

80

• 70 %
60

^ 60 %

40

-*■ 40 %

50 %
^ -30 %
20

• 20 %

10%

0

10

20

30

40

50

60

70

^0%

Time (Hours)

Fig. 93. Survival rate (%) o f A. welbourni at different relative humidities.

2. 4. DIEL ACTIVITY PATTERNS OF TWO COMMON SPECIES:
Larvae of T. auroraense became increasingly active as temperature increased
during the morning, activity peaking at 1:00 pm and then gradually declining toward 5:00
pm (Fig. 94). Among 95 individuals collected in the field, 73 were caught before 5:00
pm during the day, 22 were collected from 5:00 pm to midnight.
Larvae of L. solitarius were active both in mid-day and after dusk. The number of
larvae captured increased gradually from 5:00 pm to 9:00 pm, when the first peak was
reached. In the following four hours, the number captured dropped drastically until 1:00

174
am. After 5:00 am, the number of larvae caught rose and reached a second peak at 1:00
pm, dropping gradually after 1:00 pm. Among a total of 86 captured, 55 were collected
before 5:00 pm and 31 were collected between 5:00 pm and 1:00 am.
Based on the above data, larvae of T, auroraense tended to be strongly dayactive; larvae of L. solitarius exhibited two activity peaks during a 24-hour period, one
diurnal and a second, equally pronounced, nocturnal.
Activity patterns of mite larvae may be related to species-specific tolerance of
humidity levels. For instance, relatively high survival rates of T. auroraense at low
humidity levels in the laboratory (Fig. 91) indicate that the species is capable of
searching for hosts during mid-day. On the other hand, time of activity may be affected
by time o f hatching. Laboratory evidence strongly indicated that larvae must locate and
attach to a host very soon after emergence: if unable to do so, the majority died within
2 to 5 hours.

175

L. solitarius
NUM BER
30-1
2520

-

15 10 -

1600

2000

OOOO

0400

0800

1200

1600

2000

1600

2000

T IM E (M ILITARY)

T. auroraense
NUM BER

40

-

3020

-

1600

2000

OOOO

0400

0800

1200

T IM E (MILITARY)

Fig. 94. Diel activity patterns of two common species in a 24-hour field survey (MidJuly, 1990). Data are given in numbers of mites collected over time.

176
2. 5. OVIPOSITION AND FECUNDITY O F FOUR SPECIES.
Table 22 shows the duration of oviposition periods and the number of eggs
observed in four species (E. michiganensis, T. auroraense, L. sylvestratilis and E.
locustarum) under laboratory conditions. One hundred females o f A. welbourni were also
incubated, but none of them could be brought to oviposit.

Table 22. Duration of oviposition period and number of eggs laid per female of four
species.
Species

no. of
females

Erythraeus
michiganensis
(spring)

Oviposition days
max. min. x ± SD

no. eggB per female
max. min. x ± SD

150*

58

17

25 ± 14.0

151

50

78

34

45 ± 19.0

1084

Leptus
sylvestratilis
(spring)

70*

37

14

28 ±

7.5

108

43

77 ± 18.0

Eutrombidium
locustarum
(spring)

50*

48

27

29 ±

5.0

70

0

38 ± 10.2

Trombidium
auroraense
(laboratory)

53

69 ± 23.0

238 576 ± 74.0

* indicates field-collected individuals.

Under laboratory conditions, the oviposition period of T. auroraense lasted the
longest and the fecundity of the species was by far the highest (Table 22). It should be

177
kept in mind, however, that T. auroraense was the most easily reared of all species, and
that these females stemmed from laboratory cultures (and had thus not yet oviposited
when observations began).
Individuals o f other three species were field-collected just prior to incubation. All
exhibited shorter periods o f oviposition and lower fecundities than T. auroraense. There
are several possible explanations for these interspecific differences, although available
evidence is not conclusive: a) nutritional or environmental requirementsof these species
were not met by the rearing methods employed (e. g. A. welbourni never oviposited in
the laboratory); b) some individuals had already begun ovipositing in the field prior to
capture (e. g ., 26 o f 50 female E. locustarum did not oviposit at all), an explanation
supported by the fact that all "spring-breeders" with Type I life cycles; or c) fecundities
differ intrinsically between species. The last of these seems likely, but would need to be
supported by extended laboratory rearing.

2. 6. DEVELOPMENTAL RATES OF THREE SPECIES UNDER LABORATORY
CONDITIONS.
Table 23 shows the developmental rates o f three species under constant laboratory
conditions (18 ± 1.5 °C, > 90% humidity, 8 hours light).
Larval development time varied little between species, lasting approximately 2
weeks. Duration o f the prolarval stage (egg stage) was usually around one month for all
three species. Protonymphs, from engorged larvae to deutonymph emergence, required

178
approximately 2 weeks for development in T. auroraense and L. sylvestratilis. In E.
locustarum, the stage lasted from one month to the entire winter. Some engorged larvae
(protonymphs) of T, auroraense also entered diapause and overwintered.
It is necessary to emphasize that particular environmental circumstances can be
important for the development of a species; for instance, without cold temperature
treatment in winter, the diapause larvae of E. locustarum at room temperature could not
reach the deutonymph stage. However, when they were kept in a dark, cold room (4± 1.5°C ), 78% of the larvae molted to deutonymphs. The same was true for
tritonymphs of T. auroraense since among 50 TN kept at room temperature (17-26°C)
over winter, only 11 reached adulthood, and the emerging adults were smaller than those
kept in a cold, dark room (-4.0+1.5°C) where 87 of 100 emerged as adults the following
spring. These data indicate the importance of physical factors, such as obligatory winter
diapause, as well as nutritional demands (Table 20).
Life tables were compiled for the above three species. The tables showed that
larvae of T. auroraense and tritonymphs of E. locustarum experienced higher mortalities
of all stages under laboratory conditions, 71.5 % and 68.7 % respectively. The
mortalities of larvae and tritonymphs of L. sylvestratilis were 42.7 % and 51.4 %.
Possible reasons can be explained as nutritional requirements, that is there were not
enough hosts and prey provided to the mites and larvae and deutonymphs could not meet
their needs to finish development; second, maybe fluctuation of temperature played
important role for the species; third, niches supplied in laboratory are not favor different
stages.

179
Table 23. Duration in days of the developmental stages of five mite species under
laboratory conditions. Win. = development over winter, x and SD calculated from the
total number of individuals (in parentheses) observed in 1989, 1990, and 1991.

stage

PL

T.auroraense

L .sylvestratilis

max.min. x±SD

max. min. xlSD

max. min. x±SD

36

35

44

23

2813.2

27

(3478)

Lv

17

11

14±2.0

win. 12

1411.5

18

12

25

16

1712.0

15

12

win. 20

2212.0

31

15

67

23

3317.8
(260)

19

11

14±1.0

19±3.5

win. 35

3715.5

43

28

9

2216.7
(86)

32±4.7
(407)

87

35

42±16.0
(342)

win. 42

(177)

25

1612.0
(721)

(255)

(435)

Ad

14±3.0

35±6.5
(1446)

(321)

(621)

TN

31

(560)

(837)

DN

29±2.0
(872)

(2911)

PN

E. locustarum

46115.0
(182)

38

27

3617.5
(57)

180
Table 24. Life tables for three species under laboratory conditions, x = stage; nx =
number o f individuals alive at the begining of each stage; lx = % of original total
number (eggs) surviving; dx = number of individuals which died during each stage; qx
= % mortality during each stage.
T. auroraense

x

L. sylvestatllls

nx

lx

dx

qx

nx

egg

3478

100

453

13.0

872

100

PL

3025

86.9 114

3.7

733

84.1 173 23.6

925 63.9 204 22.0

Lv

2911

83.7 2074 71.2

560

64.2 239 42.7

721 49.9 314 43.5

PN

837

24.1

216 25.8

321

36.8

66 20.6

407 28.1

DN

621

17.8

186 29.9

255

29.2

78 30.6

342 23.6 160 46.8

TN

435

12.5

175 40.2

177

20.3

91 51.4

182 12.6 125 68.7

260 100.0

86

9.8

86 100.0

57

Ad

260

7.5

lx

dx

qx

E. locustarum

139 15.9

nx

lx

dx

1446 100

3.9

qx

521 36.0

65 16.0

57 100.0

181
2. 7. BEHAVIOR.
In laboratory and field observations, some interesting behavioral differences
between species attracted my attention. The casual observations below are given in
general for a group of related species qualitatively, not in quantitative terms.
Adults:

Trombidium auroraense tended to gather during the mating season, mainly in

spring. From late April to May, they often appeared in large numbers in wet, shadowed
mossy areas. Peaks of adult appearance were observed during mid-May in three
consecutive years, when hundreds gathered around mossy areas after a rain. Adults
frequently raised their first pair of legs and made contact with others, then moved away.
The mating behavior of this species was described by Robaux (1977), with
females picking up sperm which males had dropped or attached to the top of moss plants
(in some degree similar to the behavior of spiders during their mating season). No body
contact was observed in adults of T. auroraense. Whenever two adults were placed in
one container, only one survived.
Unlike T. auroraense, individuals of E. michiganensis always kept a wide distance
between each other. If they occasionally ran into others, they moved away as quickly as
possible. Once, I saw an injured adult eaten by an uninjured adult in a few minutes.
Casual field observations showed that E. michiganensis were able to move rapidly (the
species has very long legs) and often vigorously attacked large harvestmen, small spiders
and other mites. No gathering was observed among adults during mating seasons in the
field. Gathering also did not occur in L. sylvestratilis, L. solitarius, A. welbourni, P.
jucum and E. locustarum.

182

Adults of L. solitarius, A. welbourni, E. michiganensis and P. fucum were found
in large numbers in pit-traps since they were active on the soil surface during adulthood.
On the other hand,

L. sylvestratilis, E. locustarum, B. nonasum, A. carum and C.

curalia were frequently caught from bushes, trees and ferns by sweepneting. Adults of
all species often laid eggs in soil and underneath bark and litter.
Larvae:
Laboratory observations suggested that larval survival may be aided by the fact
that eggs hatch at different times when different numbers and species of hosts are
available. The time of hatching for T. auroraense varied from 25 to 55 days under
constant laboratory conditions. In the field, larvae of T. auroraense were active from
early July to mid-September.
Parasitic larvae are most active immediately after hatching. If they have not
found their proper hosts after 2-5 hours, most slow down and soon die. Larvae of E.
michiganensis and A. welbourni were observed to transfer from one host to another in
the laboratory (11 of 58 individuals of E. michiganensis and eight of 46 individuals of
A. welbourni respectively). This was not observed in other species.
Deutonymphs:
The stage is free-living in all species studied. In some degree, they are more
active than adults in searching for prey and shelter. They were often found in more
habitats than adults, from bushes and trees to ferns. When touched, they moved away
faster than adults in most species, and immediately entered litter, soil and fissures of
bark.

183
4. D ISCUSSION
In this study, host records showed that most mite species only parasitized hosts
in one family and sometimes in one genus (Table 18). This appeared to agree with other
current host records in many cases (Southcott, 1966, W elboum, 1983).
However, two species, T. auroraense and L. solitarius, showed wider host
acceptance than others based on Field and laboratory observations.

Trombidium

auroraense used 16 host species in the field and 19 species in the laboratory (Tables 16,
18). From July to August 1990, three species of grasshoppers in the genus Melanoplus
were the main hosts; and craneflies, flies, deerflies and plantbugs served as additional
hosts (Table 16). In an old farmland in New York State, the same species was reported
as parasite o f a single host species, the alfalfa weevil Hypera postica Gyll
(Curculionidae: Coleoptera)(V. Grandjean, 1977). Another nine species in the genus
Trombidium used a total of 67 insect species and one scorpion as hosts (Southcott, 1961
a, b; W elboum, 1983, 1987, 1989, 1991).
Leptus solitarius used 15 species in the field and 13 species in the laboratory in
July (Tables 15, 18), while L, sylvestratilis parasitized only three grasshopper species in
June (Table 17). Among 90 named species of Leptus, hosts are known for 31 o f them,
and encompass 143 species in 46 families of insects, and nine families in four orders of
other arthropods (Welboum, 1983, 1989; F a in e ta l., 1987; Southcott, 1988, 1989, 1991,
1992).
Seasonal appearance o f mite species was closely related to host preferences and
to their environmental requirements. For example, A. welbourni parasitized three species

184

of leafhoppers in the field (Table 17) and could not tolerate low humidities in laboratory
tests (Fig. 93). Larvae were frequently observed in spring and entered deutonymph and
adult stages in summer based on my personal collections and Project ELF data (Tables
9, 11). Trombidium auroraense used grasshoppers and other insect hosts in summer and
fall, and the species tolerated low humidities better than others studied in the laboratory
(Tables 10, 12, 15 and Figs. 91, 94).
In general, larvae of most mite species appeared in summer, but a few occurred
in spring and fall and parasitized hosts available during these seasons (Table 9). If larvae
of mites cannot reach full engorgement, the resulting numbers of deutonymphs and the
survival rate of the species can be low (Treat, 1975). All species have to complet their
parasitic larval stage when the seasonal hosts are available.

In addition, the life

history of E. locustarum and of the free-living B. putmani was stated to be bivoltine in
North Calorina and California orchards (Severin, 1944; Putman, 1970; Childers and
Rock, 1981). However, all species studied here, including E. locustarum and the freeliving B. nonasum, were univoltine since their larvae were observed only once a year in
the field as well as in the laboratory. This may be due to geographical divergence of the
species or to effects of different climatic conditions. Generally speaking, most species
of Trombidia are univoltine (Southcott, 1961a).
Because of adaptation to particular environmental variable and the dynamics of
host resources, many mite species have intrinsic features for surviving under long-term
unfavorable conditions. For instance, in some species, females may lay a large number
of eggs during the oviposition period when larval survival rate is low. Newell (1979)

185
obtained 80,000 to 100,000 eggs per female in Dinothrombium tm aorum (L.)
(Trombidiidae: Trombidia). In this study, T. auroraense, with the highest fecundity
among the species reared in the laboratory {Table 22), may have low larval survival rate
in the field during summer.
Based on current knowledge about competition among parasites of the same host
resource, interspecific competition may decline after a period of time through a host shift
(Colwell, 1979). In this study, Eutrombidium locustarum and Leptus sylvestratilis had
different attachment sites on the same host species in the field (Table 20). Furthermore,
more larvae o f L. sylvestratilis than of E. locustarum were found on the grasshopper
M. bivittatus, the latter being found more often on the grasshopper M. differentialis.
In two species which both attached to grasshopper wings, T. auroraense and E.
locustarum, seasonal appearance were different: larvae of T. auroraense appeared in July
and August and E. locustarum occurred in June (Tables 10, 12).
Based on field observations (Fig. 94) and laboratory tests (Figs. 91-93), activity
patterns were closely related to survival rates at different humidities. Trombidium
auroraense, which could tolerate low humidities better than the other two species studied
(Figs. 91-94), were day-active in the field (Fig. 94). Leptus solitarius, which needed
more humid conditions than T. auroraense, were active after dusk and in the morning
(Fig. 94).
Factors involved in the duration of stages can be explained as nutritional variance
between individuals o f the same species attached to different hosts (Table 20), and
different adaptations to laboratory conditions among species in the rearing tests (Tables

186
18, 22, 23). The duration o f stages under constant laboratory conditions varied between
species. For example, the maximum development time for some deutonymphs of E.
locustarum was 87 days; in deutonymphs of A. welbourni, the maximum time was only
16 days (Table 22).

187

SUMMARY

188
SUMMARY
1). From personal three-year field collections and specimens obtained over 10
years by "Project ELF" in a deciduous forest in Michigan’s Upper Peninsula, thirteen
new species and one new genus are described. Description of seven species was based
on all instars; three species were described based on larvae and adults; three species were
named from larval specimens and one was described from adults. For genera (represented
by six new species) are first records for North America: Abrolophus, Hexathrombium,
Calyptostoma and Etythraeus.
2). Host preferences of eight species of velvet mites was documented from both
laboratory rearing and field surveys. For Leptus sylvestratilis n. sp., Eutrombidium
locustarum and Trombidium auroraense, major hosts were the grasshoppers Melanoplus
differentialis, M. conjusus, and M. bivittatus. Trombidium auroraense accepted 16 host
species in the field and 19 in the laboratory, including leafbugs, crane flies, flies and
deer flies. For Leptus solitarius, hosts included 13 species in the laboratory and 15
species in the field, such as moths, craneflies, crab spiders and moth larvae. Erythraeus
michiganensis, A. welboumi, A. carum and P. jucum used aphids and other soft-bodied
insects as their hosts.
3). Based on 11 species, three types of life histories were distinguished, and
developmental stages of five species were also described based on laboratory and field
data.
The Type I life history group consisted of species which spend winters in the
tritonymph stage: L. sylvestratilis, L. solitarius, E. locustarum, B. nonasum, E.

189
michiganensis, E. septemsetalis, and T. auroraense. Four species which overwinter in
the egg stage belonged to the Type II group: A. carum, A. welboum i, C. curia rum and
P. fucum . Some T. auroraense which overwinter as engorged larvae were representative
o f the Type III group.
Under constant laboratory conditions, T. auroraense, E. locustarum and L.
sylvestratilis were reared from larvae to adults. Deutonymphs were obtained for A.
welboumi, but no adults o f the species emerged.
In general, eggs or prelarval stages o f four species lasted about 1 month. Larval
development generally required approximately two weeks. Diapausing, engorged larvae
o r protonymphs required from two weeks to an entire winter for development, variable
with species. Duration o f the active deutonymph stage also varied from 20 days to 35
days.

Trombidium auroraense, L. sylvestratilis and E. locustarum remained in the

tritonymph stage for the entire winter at a temperature o f -4 ± 1 .5 °C.
4). Mechanisms o f host-sharing were determined. For larvae o f E. locustarum and
L. sylvestratilis, soecies-soecific locations o f attachm ent on a given host allowed these
two species to coexist:
a. E. locustarum attached to grasshopper wings;
b. L. sylvestratilis attached to grasshopper antennae, mouthparts and legs.
Trombidium auroraense and L. solitarius both parasitized grasshoppers and
survived on them in the laboratory. However, they usually used other hosts instead of
competing for grasshoppers when their larval densities peaked in a given location.
Sixteen host species were recorded for the former in the field, including leaf bugs, flies

190
and crane flies. The latter was found to use seven moth species, two scorpionflies, one
opilionid and one crab spider.
In species which favored the same host resource, different seasonal appearance of the
lg^gg tended to prevent severe competition among them. Usually, E. locustarum and L.
sylvestratilis larvae were active in June and used grasshoppers; T. auroraense larvae were
active in late July and August on the same grasshopper species.
5). Responses of three dominant species to different relative humidities was
determined in laboratory experiments, and diel activity of larvae of two species was
observed during a 24-hour field survey. Trombidium auroraense tolerated low relative
humidity under laboratory conditions, but A. welbourni was very sensitive to low
humidity; responses of L. sylvestratilis were intermediate.
A 24-hour field survey showed that T auroraense were mainly diurnal, and L.
solitarius were both diurnal and nocturnal.

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