SAV""LY LARV’ AEi‘ ‘ 1‘ 1 E SUBFKMILY NEM TENAE
AI‘TACKING CC‘GIF‘. RS IN THE EORES'I‘S OF
11'}: (LuNADL 1N. ’.R\IRIES

A7 ’E‘ZiESIS
BY
EECR\E RE" RD WONG?

("15.55

This is to certify that the
thesis entitled

Sawfly Larvae Of The Subfamily Nematinae
Attacking Conifers In The Forests Of
The Canadian Prairies

presented by
Horne Richard Wong

has been accepted towards fulfillment
of the requirements for

__M_§__degree in Entomology

dMajor professor

 

Date 273///qw

0-169

 

 

SKWFLI LARVAE OF THE SUBFAMILY NEMATINAE
ATTACKING CONIFERS IN THE FORESTS OF
THE CANADIAN PRAIRIES

(
a
O
. ~-

0
0
V
‘ t
\

1 1chigan

MASTER OF SCIENCE

Department of Entomology

L; ' 1950

 

ACH‘IOVWT

Grateful acknowledgnent is made by the author to
Professors Ray Hutson and E. I. McDaniel for their sug-
gestions and constructive criticism in the preparation
of this manuscript. The assistance and encouragement
given by Mr. R. R. Lejeune and personnel of the Forest
Insect Laboratory, Winnipeg, Manitoba, Canada, durixg
the course of this work is deeply appreciated. The
information contained in this thesis was obtained while
the author was employed by the Division of Entomology,
Science Service, Department of Agriculture, Canada. It
is through the kind permission of Mr. J'. J. de Gryse,
Chief, Forest Insect Investigations, that the material
was made available far thesis purposes. This privilege
is hereby gratefully acknowledged. The writer is also
indebted to Messrs. R. Brooks and G. S. Walley of the
Systematic Unit, Division of Entomology, Ottawa, Canada,
for their determinations of the parasites reared, and to
Dr. H. H. Ross of the Illinois State Biological Survey
for his determination of an adult sawfly.

2375'45/

C O N T E N T S

 

Introduction.......................................
material and Area Sampled..........................
Nhthod of Rearing..................................
Classification.....................................
Terminology........................................

Key to Families of Sawfly larvae Defoliating

coniferSOOOooeoooooeooooeo00000000000000.0000.
MorphOIOgy Of Nematinid mwaeoooeococo-000000.000.

Key to Species of Sawfly Larvae Defoliating

coniferBOOOOOOOOOO0.0.000000COOOOOOOOOOOOOOOOC

Description of Species:
Pristiphora erichsonii (Htg.).................
Pristiphora sp................................
MOfiTOWX—Iari018(marl-o)eoeooooeooooooooooooe

Knoplo x3P0...0.000.000...oooooooooooooeoeoo
FiEonema dimmockii (Cress.)...................
Pikonema Spooeooooooooooeeoeooeeoooooeoooooooo
Pikonema alaskensis (Roh.)....................

 

 

 

 

 

Discu881on00000000000.00.90...OOOOOOOOOOOOOOOOOOOOO

ReferenCGSOOOOOOOOOOOOOO00000000000000.0000.000000.

PlatGBOOOO0.0000IOOOOOOO...OOOOOOOOOOOOOOOOOOOOO...

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INTRODUCTION

In the Prairie.Provinees the greatest damage to conifers by
sawfly larvae is caused by various species of the genus Neodiprion
of the family Diprionidae, and different genera of the subfamily
Nematinae, in the family Tenthredinidae.

The object of this paper is to present a descriptive key to
identify sawfly larvae of the subfamily Nematinae attacking;coni-
fare in the Prairie Provinces, together with a seasonal life
history of each species. During the course of the author's work
at the Forest Insect Laboratory, Winnipeg, Manitoba, a lack of a
descriptive key was evident, on the identification of the larvae
deficliating conifers. ‘A key of this nature would enable the sys-
tematist to identify the common sawfly larvae flound attacking
conifers in the Prairie Provinces, when used in.conjunction.with
the works of Atwood.and.Peck (l) on the species of Neodiprion at-

tacking conifers in Eastern Canada.

‘How Material Was Obtained and the.Area Sampled

The material used in this study was collected from.coniferous
trees in the forests of the Provinces of Manitoba, Saskatchewan and
.Alberta. Sawfly larvae were collected by dislodging them.from.the
tree onto a beating sheet placed under the branches. The dislodged
larvae were placed in containers and sent to the Winnipeg Labora-
tory, where they were reared in insectaries. Since the inception
of the Forest Insect Laboratory, Winnipeg in 1957, coniferous trees
in the Prairie Provinces were sampled regularly frmm early May to

late September.
Method of Rearing

Each insect container received by the Winnipeg Laboratory was
designated by a record number, and each species of insect in.the
container was given a subnumber, and a rearing sheet to record its
seasonal life history.

The larva or larvae to be reared were placed in jelly jars con-
taining food and a small amount of moistened soil to assist the
larvae in cocooning. In the case of larvae collected from tamarack
a little moss was placed on the bottom.of the rearing Jar. .A screen
top was placed over each jar and the record number indicated with a
wax pencil. Coniferous food in the jelly jar was changed every two
days, with the exception of tamarack, which was changed every day.

Cocoons when formed, were transferred to another Jelly jar containing

moistened cotton. The larvae or cocoons were observed every day
and any changes that occurred were indicated on the rearing sheet.

Since all the sawfly larvae studied overwintered in the
cocoon stage, they were incubated (to speed up the emergence of
the adults) by the following method. The screen lids of the rear-
ing jars containing the cocoon and moist cotton were replaced by
closed ones, and the jars packed into wooden cases in early October.
The cases were stored in the root cellar at a temperature of 40° F.
with a relative humidity of 85-90 percent.

In the second week of January the wooden cases were taken from
the root cellar, and the closed lids on the rearing jars were again
replaced by screened tops. The rearing jars were placed in the in-
cubator at a temperature of 45° F., and a relative humidity of 75
percent. The temperature in the incubator was raised two degrees
every two days until the temperature was 70° F. During the time of
incubation, the relative humidity ranged from 80-90 percent.

The method outlined above in incubating sawfly larvae was un-
fortunately, not successful for all species. Those species which
would not respond to incubation were overwintered in the ground.
The cocoons to be overwintered were transferred from the roaring
jars and placed in a two dram vial with a little mess. The vials
were corked with a non-absorbent cotton plug and placed between two
layers of moss in a screen rectangle. The rectangular screen was
placed just below the ground with the top of the screen covered with

leaf litter. About the middle of May, when the leaves of shrubs

were beginning to show, the screen rectangle was taken out of the
ground. The cocoons were placed on moist cotton in rearing jars,

and set in a cool place in the laboratory for adults to emerge.
Classification

The classification followed in this paper is the one proposed
by Ross (15). The most extensive study on the classification of
sawfly larvae made by Yuasa (18) , on the other hand, followed
closely the system proposed by MacGillivray (8), who used wing
venation as the basis for his classification. According to Ross (15)
this systen of classification was unsatisfactory due to the varia-
tions in wing venation. Yuasa in following MacGillivray's classifi-
cation grouped Diprionidae, Nematinae and Hoplocampinae, which will
be dealt with in this paper in the family Tenthredinidae. Ross'
classification gives Diprionidae family status, and groups Hoplo-
campinae and Nematinae in the subfamily Nematinae. In treating
Hoplocampinae as a subfamily, Yuasa used as one of the characteris-
tics, to separate this subfamily from Nematinae, the absence of
eversible glands on the ventrum of abdominal segments 1-7. This
characteristic is not reliable in the case of Anoplong (Marlattial,
which has eversible glands, and agrees with the definition for
Nematinae. In defining the subfamily Hoplocampinae, however, Yuasa
stated that ventral glands were usually present. There does not
appear to be a valid definition, which will distinguish this sub-

family from Nematinae in Yuasa's key, since the characteristics used

separated the three genera studied, Marlattia, Hemichroa, and
Caulocampus, from other-genera and subfamilies. The more recent
studies by Drs. H. H. Ross and R. B. Benson on classification of
adult sawflies, show such a variation from.Yuasa's classification
of the immature fbrms, that a new classification for sawfly larvae

will have to be made.

TerminOIng

To obtain uniformity in describing sawfly larvae, the plan
preposed by Middleton (10) will be followed as closely as possible.
This plan was also used by.Atwood (1) in describing Neodiprion
larvae. Where structural characters are used in this paper which
are not mentioned by Middleton, the name designated by Yuasa (18)

will be used.

Key to Families of Sawflies Defoliating Conifers

The sawfly families which defoliate conifers in the Prairie
IProvinces of Canada are:
Pamphiliidae
Diprionidae
Tenthredinidae
Only a few pamphiliid larvae have been collected, and in no in-
stances have they caused any appreciable damage; diprionid larvae

are more numerous but have never caused as much damage as

tenthredinid larvae.

The larvae of the preceding families can be separated by the
following keys

1. Antennae 7 segmented (Fig. 1). Larvae without
uropods on abdominal segment. . . . . . . . .
. . . . . . . . . . . . . . . . .Pamphiliidae.
Antennae less than 7 segmented. Larvae with
uropods present on abdominal segments . . . .

O O O O O C O O O O O O O O O O O O O O O .2.

2. Antennae 3 segmented, third segment peg-like.
(Fig. 2). Uropods present on abdominal seg-
ments 2-8 and 10. e e e e e e e e Diprionidae.

3. Antennae never with third segment peg-like.
(Fig. 3). Uropods present on abdominal seg-
ment 2-7 and 10 or 2-8 and 10. .Tenthredinidae.

Morpholog of thLLarvae in the
Subfamily Nematinae

 

 

With the grouping of the subfamily Nematime and Hoplocampinae
into the subfamily Nematinae, Yuasa's definition of Nematinae will
have to be modified to read as follows: larvae small to moderately
large; body cylindrical, slender or tapering caudad; antennae 4, 5 or
apparently only 3 segmented, conical, subconical, limpet-shaped or
flattened; thoracic legs normal in form; mesothorax consists of 4
transverse folds; third abdominal segment consists of 4, 5 or 6
transverse folds; uropods present on abdominal segment 2-7 and 10;
ventral glands usually present on abdominal segments 1-7; tenth ab-
dominal tergum with or without caudal protuberances, the number will
vary from 2 to mamr if present; setae and glandubae usually dis-

tinct though may appear to be absent on some species.

The following characteristics were noted in.the sawfly larvae
studied:

E229,' The head is subglobose, chitinized.and covered with setae.
In some species like Epistiphora erichsonii (Htg.) the head
is divided into minute irregular areas; pretentorina and
depressions along the epicranial arm and epicranial stem,
Just above the frons, distinct in larger species. The
depressions along the epicranial arm were referred to
by Yuasa as points of muscular attachment. Paired elon-
gate depressions in frons are very distinct in Pristiphora
erichsonii (Htg.) and Pikoneme sp.; labrum emarginate
along the meson; maxillary palpus with 4 conical segments;
labial palpus with 3 conical segments. The eye is sub-
globose, transparent, set in a dark brown or black circu-
lar area.

‘Antennae - The antennas are 4 segmented, flat or semi-conical;
the segments vary from.flat, ring-like or mammillate; seg-
ments 1, 2 and 3 varied from.ring-like structures to flat;
segment 4 varied from flat to mammillate. The antennal
structure will vary within certain species, and was con-
stant in others. Small white spots are evident on anten-
nal segments 1, 2 and 3; usually 2 spots on segments 2
and 3, and l or 2 spots on segment 1.

.§2§22 -‘With the exception of Anoplonyg spp. the setae are dis-

tinct on the body. Most setae are moderately long, stiff

and colored light to dark brown. The number of setae
in a given area will vary within the same species.
They appeared to be constant however on the clypeus,
and labrum. In the species examined the labrum and
clypeus each have 4 setae with 2 setae located on
each side of the structure. The mandibles have 1 and
sometimes 2 setae; the maxillary palpus generally 1
setae; the palpifer, and stipes appear to have 2-3
setae. Setae often arise from a small light circular
area on the body.

Glandubae - These are the external chitinised ring openings of
cutaneous glands of sawfly larvae. Glandubae are evi-
dent over most of the body of the species examined.

Two types of glandubae were observed; stalked glandubae
found only on Pikonema spp., are located at the end of
tubular protuberances; the sessile type found flush
'with the body, was present on.all others. The position
and location of the glandubae will vary within the same
species.

Spiracles - Spiracles are present on annulet B of the prothorax
and first eight abdominal segments. There are two types
of spiracles found on larvae of Tenthredinoidea. The
'winged type, which have semicircular or irregular chiti-

nized colored areas on each side of the spiracle, and

Thorax

 

the unwinged type, which do not have these chitinized
areas. The spiracles of the larvae examined are un-
winged or indistinctly winged.
- The thorax is composed of 4 transverse folds desig-
nated.A, B, C and D; setae are present on dorsum.of A
and C, and usually on pleurum.of B; also on the preepi-
pleurite, posthypopleurite, and thoracic legs.
Glandubae present on dorsum.of C, preepipleurite
and sometimes pleurum.of B of larger species. In.the

smaller species like.Anoplonyx spp. and Pristiphora sp.,

 

the glandubae could not be readily discerned with the
microscope. Neck plate distinct and usually the same

color as the thoracic legs.

Abdomen - The third abdominal segment consists of 5-6 trans-

verse folds indicated as A, B, Cl, C2 and D or.A, B, Cl,
CB, 03 and D. Setae are present on dorsun of B, CZ and
on C1 and C2 of the postspiracular area. Setae are also
present on the preepipleurite, postepipleurite, uropods,
epiproct, paraproct and'ventrumu Glandubae are present
on C2, uropod, postepipleurite, epiproct, paraproct and
sometimes C1 of the postspiracular area. Glandubae are
also present on the preepipleurite of the larger species,

except Pristiphora spp., where it is usually absent. In

 

the smaller species of sawfly larvae, the setae and glandu-

bae are microscopic and often indistinguishable. The

caudal protuberances, present on some nematinid larvae,
are absent on the coniferous feeding species.
Uropods - Uropods are present on abdominal segments 2-7 and 10.

In certain species like Pristiphora sp., and Anoplogx

 

spp., a rudimentary uropod is present on 8th abdominal
segment.

Eversible Glands - All species examined possess eversible glands

 

on the ventrum of abdominal segments 1-7, located between
the uropods in segments 2-7. These ventral glands varied

in shape and size, and in some species are black tipped.

1.

2.

3.

5.

6.

Key to Determine Nematinid Larvae on Conifers in the
Prairie Provinces

 

Larvae feeding on.tamarack . . . . . . . . . . . . . . . . . 2.
Larvaefeedingonspr'uce..................4.*

Larvae with black head, without stripes on dorsum.or pleurum
. . . . . . . . . . .Pristiphora erichsonii (Htg.) ... Page 12).
Larvae with yellow-brown head, olive stripes on dorsum or

pleumm O O O O O O O O O O O O O O O O O O O O O O O O O O .3.

 

Larvae without addorsal stripe on body, with dark brown patch

behind eye. . . . . . . . . . . . . . Anoplonyx sp...(Page 18).
Larvae with addersal stripe on body, without Brown patch behind
eye . . . . . . . . . Anoplonyx laricis (Marlatt)...(Page 15) .

Larvae with rudimentary uropod on 8th abdominal segment; antenp
nae subconical . . . . . . . . . . .Pristiphora sp...(Page l4).
Larvae without rudimentary uropod on 8th abdominal segment, an-
termaeflat.........................5.

 

Larvae with split olive middorsal and laterodorsal stripes,
headrfidishoryellow-brMeeeeeeeeeeeeeeee e
. . . . . . . . . . .Pikonema alaskensis (Roh.)...(Page 23).
Larvae without split laterodorsal stripe, middorsal stripe ab-
sent or partially split. Head not yelloWbbrown. . . . . . . 6.

 

Head fuscous, olive colored body, short dark green longitudinal
stripes on pleurum.joining the laterodorsal and epipleural
StriPOS. e e e e e e e e e e e e e e e Plkonema sp...(Page 21).
Head green, body green, brown dash on side of head . . . . .

. . . . . . . . . . . Pikonema dimmockii (Cress. )...(Page 19).

 

* Larvae of Neodiprion.abietis (Harr.) are very common on
spruce and—balsam in the Prairie Provinces. These larvae
can be distinguished from the above species by the char-
acteristics listed for the family Diprionidae, and the
presence of 8 olive stripes on the body. The life history
of g. abietis has been thoroughly studied by Bird (2).

 

-11..

Descriition of Speci es

 

The descriptions of the species listed below were made from

preserved specimens in the last feeding stage. It should be noted

that the color and size of the larvae will vary within species,

depending on the food and rearing conditions. Due to the limited

number of larvae examined, the number and location of setae and

glandubae may show wider variation when more species are studied.

Synonymy

Pristiphora erichsonii (Htg.)

 

(Figures 4 and 5)

gigaeonematus erichsonii (Htg. )

 

Nematus erichsonii Htg.

 

Head - Head capsule predominately black, with following parts

Thorax

 

fuscous to black: vertex, lower part of frons, ad-
frons, preclypeus and mouth parts; numerous minute
irregular areas on head; antennae subconical, segment
1 flat, segments 2 and 3 ring-like, segment 4 mil-

late; 15-19 setae on frons, usually however 17 setae

are present.

- Following parts black to light black: thoracic legs,
neck plate, paired swellings between each thoracic leg,
and postmrpopleurite; from C on the prothorax, the
dorsum (above the spiracles) is grey green, composed

of numerous fine grey green dots 3 ventrum is lightly

covered with grey green dots; rest of the thorax is

light olive green; each brown sets is set on a light
green area; 10-14 setae and 2-3 glandubae on preepi-
pleurite, 3-5 setae on posthypopleurite.

Abdomen - Same as thorax; dorsum (above spiracles) and epi-
proct grey-green; ventrum, hyp0pleurite and para-
proct sprinkled with grey-green dots; rest of body
light olive green; third abdominal segment with 6
transverse folds; 6-7 setae on preepipleurite; 6-9
setae and 2-3 glandubae on postepipleurite; 1-2 setae
on lateral aspect of uropod, with usually 1 glanduba
present.

Approximate length of larvae 18-20 mm.

The larch sawfly is believed to have been introduced from.
EurOpe in the 19th century. This insect is probably the most
serious defoliator of tamarack in North.America. It has caused
severe infestations the last few years in menitoba and Saskatchewan.
The biology of this insect was published by Hewitt (7) and Packard
(12). The seasonal life history of this species in the Prairie
Provinces is as follows:

Larva1.Activity - early June to late September.
Cocoons formed - early July to late September.
Emergence (incubation) - February.

Average days of incubation - 35.

Host - Tamarack.

Parasites: Diptera -

Bessa harveyi (Tns.)

Megaselia sp.
Fannie canicularis L.

-13- ,44,

Head -

Thorax

 

Hymenoptera -
Tritneptis sp.
mesoleius aulicus (Grav.)
Mes ol eius sp.
Chalcids

 

 

Pristiphora sp.

 

(Figures 6 and 7)
Yellow-brown.head, area along epicranial arm usually
of a lighter shade; following areas light brown to
brown; postclypeus, adfrons, mouth parts and edge of
head capsule; light areas often present on labrum,
preclypeus and mandibles; antennae subconical, seg-
ment 1 flat minute, segments 2 and 3 may be complete
or incomplete ring-like structures, segment 4 mammil-
late; frons with usually 17 setae.
- Thorax green with an olive middorsal stripe, and a
wider laterodorsal stripe, which is twice as wide as
the middorsal; both stripes start at B on the pro-
thorax and are composed of numerous olive or light
black dots; following parts light black to black:
thoracic legs, neck plate, paired swellings between
pro and mesothoracic legs; light olive patch on
preepipleurite; brown setae are not too distinct on
body; 6-9 setae and usually 2 glandubae on preepi-

pleurite; generally 3 setae on posthypopleurite.

-14-

Abdomen - Abdomen is green with the olive middorsal and
laterodorsal stripes of the thorax extending to epi-
proct; following parts also olive colored: epiproct,
prepipleurite and postepipleurite; third abdominal
segment with 6 transverse folds; rudimentary uropod on
8th abdominal segment; glandubae are microscopic; 4-5
setae on preepipleurite and postepipleurite; uropods
with zero or 1 seta on lateral aspect.

Approximate length of larvae 12 mm.
The writer is indebted to Dr. H. H. Ross of the Illinois State
Biological Survey for the identification of this species. The lar-

vae of Pristiphora sp. could be mistaken for Pikonema alaskensis

 

 

(Roh.) since coloration, markings, host and seasonal life history

resemble the latter. Unlike P. alaskensis however, the larvae have

 

never been observed to cause any appreciable damage. The seasonal

life history of Pristophora sp. in the Prairie Provinces is as

 

follows:

Larval activity - early June to early August.
Cocoons formed - middle of June to middle of August.
Emergence (incubation) - February

Ayerage days of incubation - 28

Hosts - White Spruce and Balsanu

Anoplonyx laricis (Marlatt)
(Figures 14 and 15)

Snow

Hemichroa laricis Marlatt
fiErIattia laricis (Mhrlatt)

 

-15-

H339 - Head yellow-brown; area along epicranial arm and
lower part of frons a lighter shade; adfrons, post-
clypeus, mouth parts and edge of head capsule brown
or fuscous; light areas usually present on labrum,
preclypeus and mandibles; many minute irregular areas
visible on head; antennae subconical, segment 1 small,
segments 2 and 3 may or may not be complete ring-like
structures, segment 4 mammillate; frons with usually
13 setae.

Thorax - Thorax is green with a faint olive addorsal stripe

 

and an olive supraspiracular stripe commencing on B
of prothorax; an olive transverse stripe joins the ad-
dorsal and supraspiracular stripes on B of the pro-
thorax; light yellow brown thoracic legs and neck
plate; setae and glandubae not distinct on thorax.
Abdomen.- Abdomen same color as thorax, with addorsal and
supraspiracular stripes of thorax meeting at the epi-
proct; faint olive epipleural stripe is usually visible
from A of 1st abdominal segment, and fading in.the 8th
abdominal segment; third abdominal segment with 5
transverse folds; rudimentary uropod present on 8th
abdominal segment; eversible glands on.ventrum.are
black; setae and glandubae are not very distinct on
body; setae on uropod more distinct, usually 2 present

on the lateral cephalic side.

Approximate length of larvae 14 mm.

The description of Marlattia laricis (Marlatt) by Yuasa (18)
agrees with this species, except for the supraspiracular and epi-
pleural stripes on the body. Dyar's (5) description of Hemichroa
laricis (Marlatt), Packard's (12) description of (Selandria? sp.),
and Bradely's (3) description of Anoplonz; laricis (Marlatt) agree
very closely with this species, except for the epipleural stripe.
Since no mention was made of the epipleural stripe by the various
writers (3, 5, 12 and 18), the adult form of this species was
checked to determine if it is Anoplony; laricis (Marlatt). It was
found that the adult fits the description of Hemichroa laricis by
Marlatt (9), who originally identified and described the adult of
the larvae described by Dyar (5). As a further check the adult)
disagreed with the descriptions of the other Nearctic species by
Harrington (6) , and Rohwer and Middleton (l4). Anoplonpg laricis
(Marlatt) is commonly found associated with the larch sawfly, but
unlike the larch sawfly, it has caused negligible damage to tama-
rack. The seasonal life history of this species in the Prairie
Provinces is as follows:

Larval activity - late June to late August.

Cocoons formed - very early July to very
early September.

Emergence - May.

Host - Tamarack.

Parasites: Hymenoptera -
Mesoleius sp.

Head -

Thorax

 

Ancplogyx sp.
(Figures 16 and 17)

Head yellow-brown.with a lighter shade along epi-
cranial arm, and lower part of frons; adfrons, post-
clypeus, mouth parts and edge of head capsule yellow
brown to brown; light areas often present on precly-
peus, labrum.and mandibles; many minute irregular
areas visible on head; dark brown patch on each side
of head behind eye; antennae flat with segments 2,

3 and 4 compact, and segment 1 flat and slightly iso-
lated; segment 4 is slightly mammillate, segments 2
and 3 ring-like; frons with 14-16 setae.

- Thorax green with light yellow-brown legs; fuscous
neck plate; olive supraspiracular stripe commencing
on.subdorsumtof B on prothorax; setae and glandubae

not distinct.

Abdomen - Abdomen green, with supraspiracular stripe extend-

ing from.thorax, and fading in.the 9th abdominal seg-
ment; epiproct may be tinged with light olive color;
third abdominal segment with 5 transverse folds;
rudimentary uropod on 8th abdominal segment; setae
and glandubae not distinct on.body; setae more dis-
tinct on uropod, which has 3-4 setae on lateral
cephalic side.

Approximate length of larvae 8-10 mm.

The writer believes this to be a separate species from
,Q. laricis because of the following reasons: firstly, because of
its later appearance in the season; secondly, because of the dif-
ference in coloration, size and certain morphological features,
especially the antennas; and thirdly, the setae are more numerous
on the uropod.

The adults unfortunately have not been reared to substantiate
this claim, Only a few larvae have been collected, with very little
defoliation being observed.

The seasonal life history of this species in the Prairie
Provinces is as follows:

Larval activity - late August to early September.
Cocoons formed - October.
Emergence - ?
Host - Tamarack.
Eikpgema dimmockii (Cress.)
(Figures 8 and 9)
Synonymy
Nematus dimmockii Cresson
Pachynemat_u_s_ dimmockii (Cresson)
Nemgtus ocreatus Harrington
Egg; - Head predominately green with brown dash on each side,
dorsad of eye; lighter shade along epicranial arm.and
lower frons; liglt areas usually present on preclypeus,
labrum.and.mandibles, setae dark brown; adfrons, post-

clypeus, edge of head capsule and mouth parts brown to

fuscous; antennae dark brom and flat, with all

-19-

segments varying from flat to ring-like in structure;
frons with usually 17-19 setae.

Thorax - Thorax green; olive stripe on subdorsum of B on pro-
thorax, descends to laterodorsum on the mesothorax and
then becomes the supraspiracular stripe on.metathorax;
the wide olive epipleural stripe on the spiracular
area, preepipleurite and postepipleurite of prothorax
extend to the preepipleurite and postepipleurite on
the meso and metathorax; thoracic legs and neck plate
light brown; area around setae light colored; white
spiracular stripe between 2 olive lateral stripes;
preepipleurite with usually 6-10 setae and 2-3 glandu-
bae present; posthypopleurite usually with 4-5 setae
present.

Abdomen -.Abdomen green; the olive supraspiracular stripe
from.thorax extends along the abdomen to the subdorsum
of the epiproct; wide olive epipleural strips from
thorax and on B of the 9th abdominal segment; white
spiracular stripe (between 2 olive lateral stripes)
termdnates on the 9th abdominal segment. Third abdomi-
nal segment with 6 transverse folds; preepipleurite
and postepipleurite with usually 4-6 setae and 2-3
glandubae present. UrOpods with generally 4-5 setae
on lateral cephalic side with usually 1 glanduba on

uropod, which is not stalked.

Approximate size of larvae 14-16 mm.

Only a small number of the greenpheaded spruce sawfly were
collected in the Prairie Provinces. This species has never been
known to cause serious defoliation to forest trees. The seasonal
life of this species in the Prairie Provinces is as follows:

Larval activity - early June to middle of
September.
Cocoons formed - early July to early October.
Emergence (Incubation) - February - march.
Average days of incubation - 24.
Hosts - Spruce and Balsam
Parasites: Hymenoptera -
Syndipnus rubiginosus'le.
Hypanblys BPe
Erromenus bedardi Prov.
Chalcids.

 

Pikonema sp.
(Figures 10 and 11)

[Hfad_- Head fuscous, frons slightly darker than surrounding
area; lighter shade along the epicranial arm, lower
part of frons, and preclypeus; 2 dark spots in the
light area of lower frons; 2 light brown depressions
dorsad of frons on either side of epicranial suture;
antennae flat with segments varying from flat to
ring-like in.structure; frons usually with 9-13 setae.

Thorax - Thorax olive colored; following parts fuscous:

 

thoracic legs, neck plate, paired swellings between

pro and mesothoracic legs; wdde fuscous middorsal

stripe from.B of prothorax slightly split by median

-21-

line; wide fuscous laterodorsal stripe, and epipleural
stripe on preepipleurite and postepipleurite, not

split by median line;.A and spiracular area of pro-
thorax fuscous; B of meso and metathorax fuscous, join-
ing the two lateral stripes; posthypopleurite and area
between thoracic legs on the lateroventrum is fuscous;
area around setae is lightly colored; 5-10 setae and
usually 2 glandubae on preepipleurite; postepipleurite
wdth 4-5 setae and often 1 glandubae.

Abdomen.- Abdomen olive colored; wide fuscous mdddorsal stripe,
(slightly split by median line) continues from.thorax
to epiproct, where it meets the wide fuscous latero-
dorsal stripe; epiproct fuscous; fuscous epipleural
strips from thorax terminate at 10th abdominal segment;
longitudinal folds Cl and CZ fuscous, joining the two
lateral stripes; area between.uropods on the latero-
ventrum.also fuscous. 4-5 setae and usually 1-3 glan-
dubae on preepipleurite; postepipleurite with 5-6
setae and generally 2-3 glandubae. 4-5 setae on
lateral cephalic side of uropod with usually 1 glandu-
ba,. which is not stalked.

Approximate length of larvae 14-16 mm.

This species may be a different form of Pikonema alaskensis

 

(Bch.) but the markings and color of the larvae and cocoon.wou1d

indicate it to be a separate species. Unfortunately only a few

larvae of this species were collected, and.attempts to rear it
to the adult stage by the method outlined have proved thus far
unsuccessful. The seasonal life history of Pikonema sp. in the
Prairie Provinces is as follows:
Larval activity - late July to August.
Cocoons formed - late August to early September.
Host - Spruce.
Pikonema alaskensis (Roh.)
(Figures 12 and 13)
Synonymy
Nematus ocreatus Harrington
Pachynematus ocreatus (Harr.)
Pachynematus alaskensis Roh.
Pachynematus piceae Roh.

£1359 - Head reddish or yellow-brown; lighter shade along epi-
cranial arm, and lower frons; adfrons, postclypeus,
edge of head capsule and mouth parts brown to fuscous;
light areas usually present on preclypeus, labrum and
mandibles; antennae flat, segments 1 and 4 flat, seg-
ments 2 and 3vmay be complete or incomplete ring-like
structures; frons with 12-15 setae present.

Thorax - Thorax yellowish green; neck plate and thoracic legs
fuscous. Olive middorsal stripe from B of prothorax,
split by median line; wide olive laterodorsal stripe
is split by a median line at D of prothorax; wide olive
epipleural stripe on spiracular area, preepipleurite,

and postepipleurite on prothorax and on preepipleurite

-33-

and postepipleurite of mess and metathorax not split
by median line; light olive patch on posthypopleurite,
and between.thoracic legs on.the lateroventrum; 8-10
setae and generally 3-5 glandubae on preepipleurite;
posthypopleurite with 4-5 setae and often 1 or 2
glandubae.

Abdomen - Abdomen.yellowish green; olive middorsal stripe

extends from.thorax to edge of epiproct, and split by
a median line to the 9th abdominal segment; wide
laterodorsal stripe extends to epiproct, where it meets
the middorsal stripe; distal half of epiproct olive
colored; epipleural strips from thorax extends to 9th
abdominal segment, and not split by median line; olive
' patch on postepipleurite; third abdominal segment with
6 transverse folds; preepipleurite with 4-7 setae and
generally 2 glandubae; postepipleurite with 4-5 setae
and often 2-4 glandubae. Uropods with 4-5 setae on
their lateral cephalic side with usually 1 glanduba,
which is not stalked.
Approximate length of larvae 18-20 mm.

The yellowbheaded spruce sawfly is responsible for severe
defoliations to ornamental and shelterbelt trees in Manitoba and
Saskatchewan.

Damage to forest trees by this insect on the other hand is

light to moderate in.the Prairie Provinces. The life history of

-24..

this species has been studied by Nash (11). The seasonal life

history of E. alaskensis in the Prairie Provinces is as follows:

 

Larval activity - early June to early September.
Cocoons formed - early July to middle September.
Emergence (incubation) - middle of Lhrch to
early April.
Average days of incubation - 43.
Hosts - White, black and blue spruce.
Parasites: Diptera -
Bessa harveyi (Tns.)
Wow”.
Hymenoptera -
Monoblastus sp.
Eigdipnus gaspesianus (Prom)
Erromenus sp.
moms (aphanza) sp.

 

 

 

DISCUSSION

The tenthredinid larvae attacking conifers consist of a
small compact group. Out of the ten.subfamilies in the famiLy
Tenthredinidae, only one subfamily (Nematinae) was observed
defoliating conifers; and of the twenty genera in.this subfamihy,

only three genera (Pristiphora, Pikonema and Anoplonyx), consist-

 

ing of seven species were collected from.conifers in.the Prairie
Provinces.

It is interesting to note that the food plants of nematinid
larvae studied were restricted to spruce and tamarack. The lar-
vae of Diprionidae and Pamphiliidae, which attack conifers feed
on spruce, pine, balsam.fir, and other coniferous plants, but
very rarely tamarack.

Though only indicated for the Canadian Prairies, the identi-
fied species are also found across Canada and nertheastern.United
States.

In dealing with a group of insects which is widely distri-
buted and possess diverse habits there is to be expected varia-
tions in.morphological characters. This is treated under
morphology of nematinid larvae (Page 6). The variations noted
in this section'were taken into consideration in the construction

of keys and descriptions.

-26...

l.

2.

3.

4.

5.

6.

B.

9.

10.

ll.

12.

13.

REFERENCES

Atwood, C. E. and Peck, 0. 1943. Some native sawflies of
the genus Neodiprion attacking pines in Eastern Canada.
Can. J. Research, 21; 109-144.

 

Bird, R. D. 1929. Notes on the fir sawfly Neodiprion
abietis Harr. Ann. Rept. Entomol. Soc. Gut—aria. 60:
76-§20

 

Bradely, G. A. 1939. Some common sawfly larvae attacking
conifers in northeastern North America. Thesis for the
degree of M. S. Michigan State College.

Brown, A. W. A. 1941. Foliage insects of spruce in Canada.
Canada Dept. of Agri. Tech. Bul. 31.

Dyar, H. G. 1897. On the larvae of certain sawflies.
J. New York. Entomol. Soc. 5; 18-30.

Harrington, W. G. 1902. A Canadian Anoplonyx. Can. Ento-
mol. 34: 93-94. .

Hewitt, C. G. 1912. The large larch sawfly, with an account
of its parasites, other natural enemies and means of
control. Canada Dept. Agri. Div. Ent. Bul. 10.

MacGillivray, A. D. 1906. A study of the wings of the
Tenthredinoidea, a superfamily of Hymenoptera. Proc.
U. S. Nat. Musemn. 29: 569-654.

Marlatt, C. L. 1896. Some New Nematids. Can. Entomol.
28: 251-258.

Middleton, W. 1921. LeConte's sawfly, an enemy of young
pine. J. Agri. Research. 20; 741-760.

Nash, R. W. 1939. The yellow-headed spruce sawfly in Maine.
J. Econ. Entomol. 32: 330-334.

Packard, A. S. 1890. Fifth Report U. S. Entomol. Comm.,
Revised and enlarged edition of Bul. No. 7, on in-
sects injurious ‘to forest and shade trees.

Peterson, A. 1948. larvae of Insects. Lepidopter and

Hymenoptera. Part 1. Edwards Brothers, Inc..
Ann Arbor, Michigan.

-27-

14.

15.

16.

17.

18.

Rohwer, S. A. and Middleton,'W. 1932. Descriptions of
five nearctic species of sawflies of the tribe
Hemichroini. Proc. Entomol. Soc. Wash. 34: 93-98.

Ross, H. H. 1937. A generic classification of the
nearctic sawflies (Hymenoptera, Symphyta). Illinois
Biol. Mbnogr. 15, No. 2.

Ross, H. H. 1938. The nearctic species of Pikonema a
genus of spruce sawflies (Hymenoptera, Tenthredinidae).
Proc. Entomol. Soc.'Wash. 40; 17-20.

Schaffner, J. V., Jr. 1943. Sawflies injurious to coni-
fers in the northeastern states. J. of Forestry
41: 580-588.

Yuasa, H. 1922. A classification of the larvae of the
Tenthredinoidea. Illinois Biol. Monogr. 7, No. 4.

-28—

PLATE I

-29-

CEPHALIC ASPECT 0F HEAD

Figure 1.
Figure 2.
-F1gure 30

af

0 o o
p

4 5 FJFDO

Family Pamphiliidae
Famdly Diprionidae
Family Tenthredinidae

antenna

adfrons

clypeus

eye

epicranial arm
epicranial stem
frons

labrum
mandible

vertex

 

\ U. '1 "1,

51““ .11; . _. ; .7 .‘u'

*‘ '3: ?\J- a. . ‘Kkr. _ \‘
fi.... '

~§>‘i
!I"'

6%.,
,5:fo

 

 

 

 

 

 

PLATE II

-30-

LATERAL ASPECT OF LARVAE

Note - Glandubae are exaggerated for clarity.

Figure
Figure

A, B, C
A, B,C
98

s
hypop
prep
prhyp
psa
peep
pflWP
8

ea

8p

t1

u

4. Mesothorax of Pristiphora erichsonii (Htg.)
5. Third Abdominal Segment of Prist phora

D
1, C2, 03

 

erichsonii (Htg.)

 

transverse folds on thorax

, D transverse folds on abdomen

eversible gland
glanduba
hypopleurite
preepipleurite
prehypopleurite
postspiracular area
postepipleurite
posthypopleurite
seta

spiracular area
spiracle
thoracic leg
uropod

PLATE III

-31-

LATERAL ASPECT OF LARVAE

Note - Glandubae are exaggerated for clarity.

 

 

Figure 6. Mesothorax of Pristi hora sp.

Figure 7. Third Abdominal Segment of Pristiphora sp.
Figure 8. Mesothorax of Pikonema dimmocki§_TCress.)
Figure 9. Third Abdominal Segment of Pikonema

dimmockii (Cress.)

A, B, C D transverse folds on.thorax
A, B, C , 02, Ca, D transverse folds on abdomen

eps

g
hyper
lds
mds
prep
pflWP
psa
psep
peep
8

ea
sp
sps
88
t1
u

epipleural stripe
glanduba
hypopleurite
laterodorsal stripe
middorsal stripe
preepipleurite
prehypopleurite
postspiracular area
postepipleurite
posthypopleurite
seta
spiracular'area
spiracle
supraspiracular stripe
spiracular stripe
thoracic leg

uropod

 

"‘3‘!" '9“ . p .-.. mds

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

. l
p. at“. 9...“: 1‘ s . E":- D
. r. , :v w
r 19:1 .' “'7':- I.’fli' o
n C '-' ' ”a: "' . V
5 3 2/4. '

 

 

 

 

 

 

 

 

 

 

PLATE IV

-32-

LATERAL ASPECT OF LARVAE

Note - Glandubae are exaggerated for clarity.

Figure 10.
Figure 11.
Figure 12.
Figure 13.

A, B, C1 D

Mesothorax of Pikonema sp.

Third Abdominal Segment of Pikonema sp.

Mesothorax of Pikonema alaskensis IRoh.)

Third Abdominal Segment of Pikonema
alaskensis (Roh.) -——_-__.-

 

 

transverse folds on thorax

A, B, C , C2, Cs, D transverse folds on abdomen

eps

s
hypov
1ds
mds
prep
prhyp
psa
Psep
peep
8

ea

3P
t1
u

epipleural stripe
glanduba
hypopleurite
laterodorsal stripe
mdddorsal stripe
preepipleurite
prehypopleurite
postspiracular area
postepipleurite
posthypopleurite
seta '
spiracular area
spiracle

thoracic leg

uropod

mds

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

PLATE v

-33-

Figure
Figure

Figure
Figure

A, B, C
A, B, C
ads
eps'
hypop
prep
prhyp
p88
P899
peep

8

ea
sP
8PS
t1
u

LATERAL ASPECT OF LARVAE

14.

Mesothorax of Anoplo x laricis (Marl.)
l Segment of Anoplonyx laricis

15. Third Abdomina

 

(Nar1.)

16. Mesothorax of Anoplogyx sp.
17. Third Abdomina Segment of Anoplogyz sp.

D
i, 02, D

transverse folds on thorax
transverse folds on abdomen
addorsal stripe

epipleural stripe
hypopleurite
preepipleurite
prehypopleurite
postspiracular area
postepipleurite
posthypopleurite

seta

spiracular area

spiracle

supraspiracular stripe
thoracic leg

uropod

3.

to.

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