MORPHOLOGY OF THE BRACING ELEMENTS IN
THE HYMENOPTERAN HEAD

Thesis for the Degree of M. S.
MlOHIGAN STATE UNIVERSITY
JEFFREY J. JACKSON
1956

__ - “d‘M‘s- 'ww _‘ u "2—— _

THESIS

LIBRARY

Michigan State
University

 

ABSTRACT

MORPHOLOGY OF THE BRACING ELEMENTS
IN THE HYMENOPTERAN HEAD

by Jeffrey J. Jackson

The internal head bracing elements of 56 Species representing
fourteen superfamilies of Hymenoptera were studied and described.
Strength and support of the head capsule are contributed to primarily
by the tentorium and associated inflections.

Some structures appear to have phylogenetic relationships.
Dorsal tentorial arms are best developed in primitive groups and are
either absent or vestigial in advanced superfamilies including the
Vespoidea, Scolioidea, and Apoidea. These advanced groups generally
have much more elaborately developed tentoria which include a tentorial
bridge, a feature lacking in the Symphyta.

Similar structures are found occasionally in species widely
separated taxonomically. Such similarities may be due to convergent

evolution.

MORPHOLOGY OF THE BRACING ELEMENTS

IN THE HYMENOPTERAN HEAD

BY

Jeffrey J. Jackson

A THESIS

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

MASTER OF SCIENCE

Department of Entomology

1966

-._/ / A/

/\

. ,7
i -. “4/ / \a/ ""1.
l

.7 ,

f

ACKNOWLEDGEMENTS

I wish to thank Dr. Gordon E. Guyer, Dr. Ethelbert C. Martin,
and Dr. Rollin H. Baker for their contributions to this thesis as
members of my guidance committee.

my Special thanks and sincere gratitude go to the chairman of
my committee Dr. Roland L. Fischer who has given me much technical
and editorial advice as well as continuous encouragement.

I am also grateful to Dr. Frederick Stehr for his helpful
comments and for making excellent equipment and research space avail-
able to me.

Finally, thanks are due my fellow students and friends whose
good natured kidding during periods of procrastination has helped

keep me at my research.

ii

TABLE OF CONTENTS

Page

INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . l
TERMINOLOGY . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Anterior Arms . . . . . . . . . . . . . . . . . . . . . . . . 4
Dorsal Arms . . . . . . . . . . . . . . . . . . . . . . . . . 6
Posterior Arms . . . . . . . . . . . . . . 6
MEGALODONTOIDEA . . . . . . . . . . . . . . . . . . . . . . . . . 7
CEPHOIDEA . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
TENTHREDINOIDEA . . . . . . . . . . . . . . . . . . . . . . . . . 10
SIRICOIDEA . . . . . . . . . . . . . . . . . . . . . . . . . . . l4
ICHNEUMONOIDEA . . . . . . . . . . . . . . . . . . . . . . . . . l6
CHALCIDOIDEA . . . . . . . . . . . . . . . . . . . . . . . . . . 19
CYNIPOIDEA . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
PROCTOTRUPOIDEA . . . . . . . . . . . . . . . . . . . . . . . . . 25
BETHYLOIDEA . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
SCOLIOIDEA . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
FORMICOIDEA . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
VESPOIDEA . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
SPHECOIDEA . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
APOIDEA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

BIBLIOGRAPHY . . . . . . . . . . . . . . . . . . . . . . . . . . 51

iii

10.

ll.

12.

13.

14.

LIST OF TABLES

Structures of the Internal

Head

Megalodontoidea and Cephoidea

Structures of the Internal
Tenthredinoidea . . .

Structures of the Internal
Tenthredinoidea . . . .

Structures of the Internal
Siricoidea . . . . . .

Structures of the Internal
Ichneumonoidea . . .

Structures of the Internal
Ichneumonoidea . . . .

Structures of the Internal
Chalcidoidea .

Structures of the Internal
Cynipoidea . . .

Structures of the Internal
Proctotrupoidea

Structures of the Internal
Bethyloidea

Structures of the Internal
Scolioidea . . . . . . .

Structures of the Internal
Formicoidea . . . . . .

Structures of the Internal
Vespoidea . . . . . . .

Structures of the Internal
Sphecoidea . . . . . .

Head

Head

Head

Head

Head

Head

Head

Head

iv

Skeleton

Skeleton

Skeleton

Skeleton

Skeleton

Skeleton

Skeleton

Skeleton

Skeleton

Skeleton

Skeleton

Skeleton

Skeleton

Skeleton

of the

of the

of the

of the

of the

of the

of the

of the

of the

of the

of the

of the

of the

of the

Page

11

12

15

17

18

20

23

26

28

31

33

36

39

Table

15. Structures of the Internal Head Skeleton
Sphecoidea . . . . . . . . .

16. Structures of the Internal Head Skeleton
ApOidea O O O O O O O O O O

17. Structures of the Internal Head Skeleton
Apoidea . . . . . . . . . . . . . . .

18. Structures of the Internal Head Skeleton

Apoidea . . . . . . . . . .

Page

of the
O O O O O O O 4]-

of the
. . . . . 44

of the
. . 45

of the
46

Figure

LIST OF FIGURES

Page

Terminology of Facial Sutures and Ventral Aspect
of Head Capsule . . . . . . . . . . . . . . . . . . . . 5

The Internal Head Skeleton of Megalodontes
cephalotes (Megalodontoidea), Cephus tabdus
(Cephoidea), and Tenthredo basilaris
(Tenthredinoidea) . . . . . . . . . . . . . . . . . . . 13

 

 

 

 

The Internal Head Skeleton of Tremex columba
(Siricoidea), Megarhyssa m. macrurus
(Ichneumonoidea), and Chalcis microgaster
(Chaladoidea) . . . . . . . . . . . . . . . . . . . . . 21

 

 

 

The Internal Head Skeleton of Diplolepis rosae
(Cynipoidea), Pelecinus polyturator
(Proctotropoidea), and Trichrysis tridens
(Bethyloidea) . . . . . . . . . . . . . . . . . . . . . 29

 

 

 

The Internal Head Skeleton of Campsomeris
guadrinmaculata (Scolioidea), Camponotus
pennsylvanicus (Formicoidea), and Vespula
maculata (Vespoidea) . . . . . . . . . . . . . . . . . . 37

 

 

 

 

The Internal Head Skeleton of Chlorion i.
ichneumon (Sphecoidea) and Andrena helianthi
(Apoidea) . . . . . . . . . . . . . . . . . . . . . . . 47

 

vi

INTRODUCTION

The tentorium is an internal head structure found only in the
insects and is the most important of the bracing elements within the
head capsule. It consists of strengthening struts which are formed
by two pairs of cuticular invaginations that unite within the head.

Major general works on the insect tentorium include Snodgrass
(1935 and 1956) and Matsuda (1965). These references, where discussing
the tentorium, are primarily concerned with theories of origin, evolu-
tion, and general statements of function.

Hudson (1945, 1947 and 1948) has described the tentorium as
found in the Orthoptera, Dermaptera, Isoptera, Odonata, and Plecoptera.
There has been no general study on the tentorium of the Hymenoptera,
but a few limited primarily to descriptions of single species. The
honeybee (Snodgrass, 1956) is an outstanding example and Michener
(1944) described the tentorium of Anthophora.

Some valuable information closely related to the hymenopteran
tentorium can be gleaned from work done on sutures and the external
facial morphology of the face of Hymenoptera (Bigelow, 1954) and the
clypeus and the epistomal suture in Hymenoptera (DuPorte and Bigelow,
1953). The relationship of the tentorium to the epistomal suture and
strengthening inflections that are associated with it are well

described.

This paucity of published information has lead the author to
investigate the morphology of the internal supporting mechanisms of
the hymenopteran head.

No one appreciates better than the author the incomplete nature
of this work; for representatives of only 56 species and fourteen
superfamilies have been studied intensively. The tentorium and
associated inflections which illustrate the various ways in which
strength and support of the head capsule may be achieved are described

for each of the taxa.

TERMINOLOGY

Descriptions presented herein pertain to the location of the
anterior tentorial pits, the shape of the anterior arms, the rear
insertion of the anterior arms, dorsal arms, tentorial bridge, spine,
and internal inflections. This terminology is used consistently in
the discussion of the morphology of the bracing elements of the
hymenopteran head.

The number and complexity of facial sutures may vary consider-
ably from group to group and from species to Species. The sutures,
when invaginated internally, form inflections which add to the bracing
of the head. The Clypeogenal Inflection extends from the anterior
mandibular articulation to a pit demarking the anterior external in—
vagination of the anterior arm of the tentorium, known as the Anterior

Tentorial Pit (abbreviated herein as ATP). In Fig. 1A only the clypeo-

 

genal sutures are present. In Fig. 1B the ATP are connected by the
Epistomal Suture, a suture extending between the two anterior pits.

Other sutures that may be present and inflected include the Frontogenal,

 

(Fig. 1C), which extends from the anterior pits dorsally to the base of
the antennae, and the Mala; which extends from the base of the compound
eye to the region of the posterior mandibular articulation.

Compound eyes (Fig. 5E) are nearly always ringed with an Ocular
Inflection but in some cases it is nearly absent (Fig. 1D).

3

The postgenae, the lateral and ventral parts of the occipital
arch, may be inflected (Fig. 4C).

Union of the inflected postgenae with the face is seen in some
Specimens.

When most hymenopteran head capsules are viewed from the ventral
side with the mouth parts removed a single large opening is seen,

Fig. 1E. Usually the rim of the opening is thicker than the remainder
of the exoskeleton.

There may be slight indentations which tend to isolate the man-
dibular sockets (Fig. 1F). Some species, however, have the mandibular
sockets completely isolated so that there are three openings in the
ventral head capsule (Fig. 1G).

Separate mandibular sockets as in Fig. 1G probably provide

the greatest mandibular support.

Anterior Arms

 

The Anterior Arms in their simplest form are approximately

 

cylindrical and extend from either side or below the occipital foramen
to the anterior tentorial pits which are commonly found not far above
the anterior mandibular articulations (Fig. 4B). Frequently, however,
the arms bear extended flattened areas termed, wings, which may be
lateral (Fig. 3A) or vertical in position (Fig. SC). The wings may

be so greatly expanded that the anterior arms may have the appearance
of elaborately twisted ribbons (Fig. 5E). If the anterior arms are
flat the ATP will be slits and may occupy nearly the entire clypeogenal

and/or epistomal sutures. (Fig. 10, 5E).

Fig. 1. tsrnlnology of hols]. sutures and ventral
aspect as had capsules.

Dorsal Arms

 

Dorsally, and usually about at their mid point, the anterior
arms give rise to Dorsal Arms. These may be strong and attach solidly
to the face (Fig. 3C & D) or absent (Figs. 4A, 5C). Intermediate
degrees of development of the dorsal arms are common. In such in-
stances dorsal arms may not extend all the way to the face. They may
be mere vestiges which are difficult to see and are easily broken off

while preparing the Specimen (Fig. 5E).

Posterior Arms

Immediately anterior to the occipital foramen Posterior Arms

 

may extend upward and mesaly from the anterior arms and join to form
the tentorial bridge. Commonly a slender projection, the §ping, ex-
tends forward and/or downward from the center of the bridge. In

rare cases the posterior arms are not joined (Fig. 4B). Posterior
arms are absent in many Hymenoptera (Fig. 3B) but the occasional
presence of a spine at the juncture of the anterior arms suggests that

in these cases it may be fused with the anterior arms (Fig. 2F).

MEGALODONTOIDEA

Figure 2A and B

Megalodontes cephalotes Fabricius has a fairly simple tentorium.

 

The dorsal and anterior arms are smooth rods of about the same size.
The dorsal arms are solidly attached to the face just above the antennae.
The anterior arms meet the face midway between the antennal sockets
and anterior mandibular articulation. On the ventral side, at the
point of attachment to the face, is a short inflected area of the
clypeogenal suture. There is no visible reinforcing ridge connecting
the anterior arm and the anterior mandibular articulation. The rela-
tively weak appearing sickle shaped mandibles of this species appar—
ently obtain little support from the anterior arms. Perhaps a well
differentiated supportive mechanism is not necessary for the adults
are believed to feed mainly on pollen.

The posterior arms are very prominent. The tentorial bridge
appears as a flat ribbon in the shape of a squared off horse shoe.
A small spine extends toward the lower face from the bridge. The
bridge is situated low on the anterior arms and cannot be seen through

the occipital foramen.

CEPHOIDEA

Figure ZC and D

The anterior arms of the tentorium are arc shaped, laterally
compressed posteriorly, and fused at the base. They meet the face at
the anterior mandibular articulations and at this point the arms are
dorsoventrally flattened. The dorsal arms are fairly Stout rods and
meet the face just laterally and slightly above the antennal insertions.

There is a median Spine at the angle where the anterior arms meet.

 

wasmmmo mam: mo omma

ccsoum mwwwu nuw3 woman on ou mummmmm
unamEoumHmo .mH< mo Gowuwmoa 30H on

map ucmmnmunamcmwomahfio .EdwcmEuuumasoo

mEum “caumucm mo cofiuocsn um muuom

-cH .mmmn msow>no nuHB usn .xmm3 hum>
ucmmn<

momma

amazoucm m>oam umsm wcwuummcwinwcouum

HmUMmHooo osu
BoHon umsn wcfluummcfl .mommn umoc woman

mono HoHuoucm mzu um
kHHmumumH cmccmmxm cam mcfl>udo UHchBOQ

COHUNHDUHUHN HNHDDHUCME .HOHHQUCM GSU u<

mmfinwwcme commam maxowm .wcwumoaam xmoB

oHEHUGmE ou mcflmcouxo uo: use
mH¢ Sedan umsh wouomflmaw Hmcmwooahfio

.qumnm HmEOumflmo .wmaofim>ow HHm3 amazoo

uammoum

cowuomm
mmouo CH oxHH connflu .umam .wmoum

omccoucm ecu o>onm umdm mowm ocu wooe
monu .mEum HOwuoucm mzu mo umumEmHv
mau N\H mwou HmoHHbCHamo nuooEm
mwcaun

HmEOumoahz mo unma umoE HOwumuc<

mvou Hmowuvcwfiho nuooEm

mmccmucm mo momma BoHom

mHszZOU mmmHO

mZOHHUMAmZH

MZHmm

mumHmm A€HMOHZMH

m2m¢ A<mmoo

mzm< MOHMMHZ< mo
ZOHHMMmZH m<mm

mzm< MOHMMHZ<
me mo mm<=m

mH<
mmH mo ZOHH<UOA

 

 

msowunmm mapwnmu msammo
mmeasamo

 

msfiowunmm mmuoflmsmmo mmucowofimmoz
mmcwucoconwmz

 

 

<mQHommmo Qz< <MQHOHZOQOA<OMZ.MSH mo ZOHmAMMm Q<mm A<ZMMHZH MIR mo mMMDHUDMHmuI.H mamflH

TENTHREDINOIDEA

Figure 2E and F

The anterior tentorial arms may be flattened, twisted, or with
mesal wings as in Tenthredo. Clypeogenal inflections may be present
if the insertion of the anterior tentorial arms is remote from the
anterior mandibular articulation. In Cimbex, the insertion of the
anterior tentorial arms is remote but the clypeogenal inflection is
not developed. A small apodeme is present on the ventral side of the
anterior arms near the near insertion in Cimbex and Tenthredo. The
rear insertion of the anterior arms is often at the inflected post-
genae. Dorsal arms are strong and join the face near the antennal
bases. Posterior arms are not present, but a spine projects anteriorly
from the fork of the anterior arms of Tenthredo.

Inflections are in general fairly well developed with the
exception of Cimbex in which internal supporting inflections are
lacking, including the usually conspicuous ocular inflections of other

forms. This may be compensated for by the thick exoskeleton of Cimbex.

10

11

 

Hmcowomahfio .HmEoumwam .umasoo
ucmmn<
ucomn<

momma Hmccwucm ocu mo
HmumumH m>onm mafisomuum .usoum hfiuflmm
:mEmuow Hmuwawooo BoHon umsh

coumHBu
uMLBmEOm cam mflflmuucm>0mpoc vocmuumflm

coHumasofluum umH:
-nficcma uoHumucm onu mo Ummme maunwwam

cam o>onm mmMSusw anamwomahao cam
HmEOmemm mnu mo unma wcflcsaocwuumuwfim

COuonxmoxo xowsH
ucomoua uoc Hmcmwomahao mam HmEODmHam
ucomn<

ucomn<

momma Hmccmucm
m>onm mflmumflcoEEH wcw£UMuum .u30um
mmcowumom cmuooHMCH

osmvoam wcHuoonowa
oum3c30w HHmEm cows .xoflnu .uHOSm

mmmn Hmccmuam mam coHumHSUHuum
umfisnwwcme uofiuoucm cmoBumn hm3cfiz

mHZMZZOU mmmHo

mZOHHUMAmZH

mszm

mmemm A<HMOHZMH

mzm< A<mmon

mzm< MOHMMHZ< mo
ZOHHmmmzH m<mm

mzm< MOHmmHz<
mmH mo mm<mm

mH<
mmH mo ZOHH<UOA

 

 

Anouwmv woucoowa :oflumqvooz
mmuHcoHuaHQ

 

 

soqu mcmowumEm xonEHu
mmvwofinswu

 

 

 

<MQHOZHQMMZHZMH Mme mo ZOHMAMMm Q<mm A<ZMMHZH mmH mo mMMDHODMHmui.N mqde

12

 

mmkm omumg

wcouuwunamcmwoma%ao
.wcouum muo>nnamEoumHmo .umHSoo

ucown<

unmmn<

umxoom Hmacmucm mo
wwwm Hmumumfi um wcwuuomcw paw EDmeE

mmcowumom wouoonaH

cmumwsu bum commouQEoo kHHmuoumq

maowumadofluum
umasnwpame Howuoucm mo vmmoE cam o>on<

waouumuuflmcmwoomhfio
.waouum %Huflmmu-HmEoumHmm .umadoo

ucomn<

ucmmn<
momma Hmccmuam o>onm wcw£UMuum .uDOum
cowuoofimafl Hmmeumom HHmEm cu wouooccou
mEooomm wcwuomnoum Unm3c3oc

HHmEm auHB mowvo ammoE mzu so mcoHu
uommoum Hmumumfl cmamuumaw hflamofiuuo>

momma Hmccoucm Bonn umsh

mHZMZZOU mmmHO

mZOHHUMAmzH

mZHmm

MUQHmm A¢HMOHZMH

m2m< A<mmon

m2m< MOHMHHZ< mo
ZOHHMmmZH m<mm
mZM< MOHmMHz¢
mmH mo mm<mm

mH<
mzH mo ZOHH<UOA

 

 

Ammmv mfiumfisaawo msfiwzmoom5mw
mmeawu<

 

mmm mHCmHHmmn ocoHSucmH
omcwaflcmunucma

 

 

<MQHOZHQMMSHZMH mmH mo ZOHMAMMm Q<mm A<ZMMHZH mmH ho mMMDHUDMHmnI.m mqm<H

1'19. 2, AJ, malachite! ceghslotes. legllodontoidos:
0,3, Coflus tsbidus, Cephoides: IJ, zenthredo
beggar“, Tenthredinoidea.

 

FIG. 2

SIRICOIDEA

Figure 3A and B

The thick walled head of Tremex is supported by a relatively
simple tentorium. The anterior arms are fused into a single rod
posteriorly, and adorned with small, flattened lateral wings anteriorly
on each side--the mesal wings being larger. Where the anterior arms
meet the face they join a moderately thickened clypeogenal inflection
that connects them to the anterior mandibular articulations. Strong
dorsal arms are attached solidly to the face above the antennal bases.

The tentorium of Xiphidria maculata is very similar except the

 

anterior arms lack the flattened wings and the tentorium is bent
sharply downward posterior to the origin of the dorsal arms. For
this reason the dorsal and anterior arms join the face slightly lower
than in Tremex.

The ventral edges of the head capsule are strengthened in both

species.

14

15

 

muonum

madmamo mo momma Hmuucm> .umflsoo .xofinu
zuo> mcoHumasoHuum wmfisnwucme uoHumucm
cam mH< cowsumn mmum .xmmz HmEouwwmm
onoHH GH m4

memuH aw m4
onmuH CH m<
meouH aw m<
mew3 Hmuouma oz .vum3c3ov anon

mum mEHm coflumumamm mo ucHoa mnu u<
.cou cHHom coca coma“ «Hm: Howumumom

memuH aw m<

xownu coumamxmoxm .HHmEm mm%m

mcouum umfiaoo .maouuw

madmmmo cam: mo mowvm Hmuucm> .xowzu
cam cwoun Hmcwwowmmao .xmo3 Hm80umwam
ucomc<

ucmmp<

momma Hmcsmucm
mnu m>onm oomm oLu wcw:w0m .wcouum

amEmMOM Haufiawooo oau BoHon two:
man mo xomn msu momma coy meCwm msH

tow

meCHm m OucH mfiuoflumumoa woman .mowwm
soon do mwcfis Hmpmuma cocmuumHm JuHS

GOwumfisowuum smasnwccme nowuoucm o>on<

mHzmzzco MmmHo

mZOHHUMAhZH

MZHmm

MUQHmm A<HMOHzmH

m2m< A<mmom

m2m< MOHMMHZ< mo
ZOHHMMWZH m<mm
mzm< MOHMMHZ<
mmH mo mm<mm

mH<
mmfi mo ZOHH<UOA

 

 

mumHDomE wwucflsmwx
mmeaaueaaaax

<mmHoonHm mmfi mo ZOHMAMMm Q<mm A<ZMMHZH mmH mo mMMDHUDMHmIn.¢ mqm<H

 

AmSmmccqu mbEDHoo meme
wmvwowuwm

ICHNEUMONOIDEA

Figure 3C and D

The tentorium and other aspects of the internal head skeleton
in this group are structurally quite consistent. The anterior ten-
torial pits are found immediately above the anterior mandibular
articulations or in some instances at the anterior mandibular articu-
lation. Where they meet at the face the anterior arms are often
dorsoventrally flattened. The wings extend laterally for at least
half the length of the anterior arms. The anterior arms may either
fuse posteriorly into a single median rod which connects below the
occipital foramen or, if the postgena is inflected they may join it
instead. Dorsal arms are usually well developed and connect to the
face in the vicinity of the antennal sockets. The tentorial bridge
bears a spine. The inflections joining the ATP and also connecting
to the mandibular articulations are not especially well developed.

Agathis appears to be an exception in some of its morphological
features for it differs from other members of the group in several re—
spects. In this species the deeply inflected postgenae connect with
the short, relatively unmodified anterior arms. Dorsal arms, the

tentorial bridge, and spine are lacking.

16

l7

 

Hmamwommxfio
.HmEOumHQm .mcouum guanoo

uammmum

:mEMHOM
Hauwawooo mamam .ucomoum

mumeOm Hmccmuam mo

mambo Hmuouma um wcwuuowafi
oumowamc .Hoocoam .mcou

Hmcwwumoa wouomamcH

mwGflB
HmumumH cmcmuumHm Luflz

mcowumasowuum
unadnwccmfi Hofiumucm o>oa<

xmm3 HmEOumwam .umHSUO

ucmmoum

usoum @ HHmEm

mumeOm Hmacmucm mo capo
numH a 3onn umsn wcwuuom
nag .oumowfimv w umvaHm

:mEmHom Hmufiawooo
Scamp muoocaoo cow mech

:m: a mafia umamnm ma coup
-oom mmouo wmcwnsoo umnu
ow kHHoHumuam moamuuwam
.hfiuowuoumoa woman

maoHumfidoHuum
umfisnwccms Howuoucm mo
cmmma .mudusm HmEoumwmm

Hmaowomamfio
wcouum .umHSUO .HmEoumHmm

unomn<

ucomn<

ucomb<

momm ou maummc monouxo

owwwununowcwun HmEouwoakm

mwou uuosm huo>

mcoHumHDUHuum
smasnwccme Howumucm m>on<

mZOHHUMAmZH

mszm

MUQHmm A¢HMOHZMH

m2m< A<mmon

mzm< MOHMMHZ< mo
ZOHHmmmZH m<mm

mzm< MOHMMHZ<
mmH mo mm<mm

mH<
NIH mo ZOHH<UOA

 

uo3£om

 

msuo>wdwucm magnumoouomz
omcwcoomum

Axooumw>v
mHoowEH: wsfioomdMu<
omvHaoomum

 

wonocm>oum
coumHnau manumw<
mmvwcoomum

 

 

 

<mQHOZQZszmUH mmH mo ZOqumMm n<mm A<ZMMHZH HEB mo mMMDHUDMHmun.m mqm¢H

l8

 

HmEoumHmm .umHSUO

ucmmoum
ucommum

mumeOm amazouam mo
vapouma wcfluummcfi .wcouum

:mEmuom Hmuwmfiooo
Bonn uumm:« mEum woman

kHquumucm umcHB wcwEooon
cocmuumaw mflfimnucm>0muom

maowumfinowuum
umasnwwcme powumucm u<

xmo3 hum>
-iHmcmwooaxao .umasoo

mymBfiBoc
wsfl>udo cmzu mam cumB
-uom wcwocmuxo .ucmmmum
ucommum

mumeOm anaconda

m>onm mafinomUum .xmmB

owcwun HmEoumomms u<

mwcHB moHB Lugs
bmcmuumam zfiflmuucm>0muoa

mcoflumH
isofluum umflsnwwcme o>on<

umHDUO

wamS
-CBOc wcHucwom uuma Hmu
imam oumoflamv m cam cum3
nMOM wcwccouxo uuma Hmmmn
wwflum m now: ucmmmum

ucommum

muoxoom Hmaamuam
m>onm wcwcomuum .xmoB
mwcwun Hm80umoa%£ u<

mauowumucm Howw3 wcHEooon
bocmuumflw %Hfimuuao>0mnoa

mcowumHsoHuum
umfianwwcms uofluoucw o>on<

mZOHHumAmZH

MZHmm

moaHmm AfiHMOHZMH

m2m< A<mmom

mzm< MOHmmHz< mo
ZOHHMMmzH m<mm

mzm< MOHMMHZ<
mmfi mo mm<mm

mH<
mmH mo ZOHH<UOA

 

mammccflq
mauspome .m.mmm%£ummoz
omcflcossmacoH

 

AcmELmsov
Hmmm mwfimuoz
mmvwcoesocsoH

 

Axooumfl>v msawucwdm

 

mmmflumHDGCm :oEDmGSowumuo
omcwcoescmsoH.

 

 

<mQHOZOZszmUH mmH mo ZOHMAMMw Q<mm A<ZMMHZH mmH mo mmMDHUDMHmai.© mqm¢H

CHALCIDOIDEA

Figure 3E and F

The ATP of the Chalcidoidea are usually located just above the
anterior mandibular articulations and may be either a spot or slit-
like in form depending on the cross sectional shape of the anterior
arms. The anterior arms may continue as separate rods to join the
back of the head on either side of the occipital foramen or they may
fuse into a single structure which bounds the occipital foramen on
three sides. If this is the case, the tentorium is fused to some
degree with the inflected postgenae.

Great variation is exhibited in this group in the form of the
tentorial bridge. In some cases it is fairly typical and bears a
spine. Of the specimens examined the spine is present in two species,

absent in one species, and in Chalcis microgaster the posterior arms

 

do not meet in the center--an unusual condition. The tips of the
posterior arms are pointed forward. Supporting inflections in the
face and mouth area are in general not as well developed as in the

more advanced Hymenoptera.

l9

20

 

mcowumasowuum umflsnwccme
noon ou wcfluooccoo udn mH<
hp xfimwuma vowa:ooo-namcmm
nomamao .oaoaunHmEOumflam

ucmmn<

HmUHawooo mamamniucmmmum

muoxoOm Hmccmucm mo scam
umcuwo um momm ou wcHuooc
icoo @ bmaon>mc HHmB

mwoamco CH
mm omcowumoa mouomamcH

hfiuowumuwoa woman cocoa
-umHm ouafl wouwcn .wco
“Owuouam um onoH ammoE
:ufls mafimuoumfl mmcouumam

mcoHumHSUHuum
“mannwccme nowumucm m>onm
manusm Hmcmwooazfio ca
coucmfluo mfiamowuum> zflummz

HmEOumfiam..umH:oo
owpfium HawuoucmH mom

mafimm uwflam mama ummaam
ou cumzuom monomuflc mum
mmSH .umoE uo: oc mono usn
uaomoua mum mEum uofluouwom

muoxoOm
Hancouam mo cmumumfi oomw
ego wcfiuooe mvou HoccmHm

cmEmuom Hmuw
lagooo ecu mo ovwm Mosuwm
ou owcwu m mm wcwscwucoo
usn .mmaowumom wouooamcH

vapouma mwco umBoH
.umasowbcmaumm mfiu Eouw
oncm omq um cosmuumam

wcoHumadoHuwm
unfinnwccme wowumucm
cu wcHuooccoo d m>on<

ucmmnm HmEoumwmo
Hmcowomamao .umasoo

unmmmum

ucommum

ucomn<

coEmuow Hmuwawooo onu mo
owwm uocuflm co 6 zofiom

woos wcw>udo
czow .LuooEm .umvaoam

mcowumfisowuum umH:
unaccma MOmeucm onu o>on<

monHomquH

mszm

mwnHmm A<HMOHZMH

mzm< A<mMOQ

mzm< MOHMMHZ< mo
ZOHHMMmZH m<mm

mmH mo mm<mm

mH<
mmH mo ZOHH<UOA

 

ham
mwcfimmm mammoosmq
omwwamoosoq

 

hmm
“mummwOMUHE mfloamnu
mmvficaoflmso

 

maaaaanm
m>umm mumum>n mEoumusm

mmcflEOuzusm

 

 

 

<MQHOQHUQ<IU mmH mo ZOHMAMMm Q<mm A<ZMMHZH mmH mo mMMDHUDMHmIn.m mqm<H

119. 3, AJ. gram: 20m, 8111020141“:

cm. W 3 “crux-us, Ichneumonoidea;

3.). Chang; W, Chslctdotdss.

 

 

 

   

FIG. 3

CYNIPOIDEA
Figure 4A and B

The ATP are located near the anterior mandibular articula-
tions. The anterior arms vary from straight, smooth, parallel rods
to flattened and twisted structures. They connect posteriorly at
either side and/or below the occipital foramen but may also be
partly fused with inflected postgenae (Xyalophora). Dorsal arms
may be well developed or absent. Posterior arms may be joined to
form a tentorial bridge or they may be unjoined as in Diplolepis.
If the bridge is complete there is a Spine. Inflections are gen-

erally weak.

22

23

mH< mo :ofiuflmom 30H Ou mac unocm
Hmaowooazflo .xmoz HmEOOmwao .umHSUO

udmmwum

ucwmmum

mumwXUOm HWCCQUCN WC HNHQUMH COHUHNwCH

cmEmu0m HMuHmHooo Boamm

cuflsu uoHumucm
msu CH mafiwuoumfi wcfiumam moon uswwmuum

mCOwumHSUwuum umfisnfivame
uonoucm osu o>onm mam nonumwOu mmoHo

vmuomamcw omcmwumom

mH< mo cOwuHmom 30H on one
uponm Hmcowommmfio @ HmEOumHmo .umHSoo

mwvwwa HmHHOucou mom
ocwam

uHHmm m waH UHmBMOM wcfiuoomoum cam
cocfiOH uoc use ucmmmua mEum wofiumumom

ucomn<
cmEmHOM Hmufimwooo
mo mvwm pmnuwm um mam mo owmn u<

mvou nuooEm .Hmaamuwa .uswfimuum

cofiumasowuum HmHDwaGmE Howumucm m>on<

mHzmzzoo MMEHO

mZOHHUMAhZH

MZHmm

MUQHmm A<HMOHZMH

m2m< A<mmoo

mzm¢ MOHMMHZ< mo
ZOHHmwmzH m¢mm

m2m< MOHMMHZ<
mmH mo mm<mm

mH<
mmH mo ZOHH<UOA

 

 

cmEomem mwccmmwfisome mwamnH
oonHmQH

 

Amsmwccqu mmmou wwamfiofimwm
mmvfiawcho

 

 

<mmHomHZMU mmH m0 ZOHmAmMm Q<mm A<ZMMHZH WEB mo mMMDHUDMHmui.w mqm<H

24

 

uhOfimuuHmcmwommkao .HmEoumwao .umHDQO
ucmmmum

ucmmmum

ucmmn<

coEmuom Hmuwawooo mo vmumumq

mwou .cuooEm .unwwmuum

mcoHumflsowuum
umfisnwccms u0wuoucm mo vamme cam m>on<

wmuooawcfi mmcmwumom
ucowoum
ucommum

mumeOm Hassoucm mo
vmuoumfi momm ou wcwuooccoouimcouum

Hmcmwumom vouomfiwaw cu mauumm
cam cmEmuow Hmuwmwooo mo mvwm nonuwm

mam: HoHumucm How
AHHmuucm>0muoo mocmuumfim mam moumwSH

mxaauaam--
mCOHUmHDUHUHm HMHSDHUCME HOHHQUCQ O>Oߢ

mZOHHOMAmZH

MZHmm

monHmm A<HMOHZMH

mzm< A<mmon

mzm< MOHMMHZ< mo
ZOHHmmmzH m<mm

mzm< MOHMMHZ<
mmH mo wm<mm

mH<
HEB mo ZOHH<UOA

 

 

Amwuummv HOumcwsmw mwuhsuwafimo
mmvflmwcmu

 

Ammmv mumoawamnuaflmm.muosmofimww
mmeauawam

 

 

..n-....--. a _-

PROCTOTRUPOIDEA

Figure 4C and D

The ATP are found very near the anterior mandibular articula-
tions. The anterior arms are usually not greatly modified and may be
united into a single rod posteriorly. Their connection to the back
of the head is at either side and/or below the occipital foramen or
to inflected postgenae. Pelecinus is exceptional in having the
anterior arms nearly entirely fused with deeply inflected postgenae.

The tentorial bridge, if present, bears a spine.

Inflections are generally weak but this deficit is probably

compensated for by a relatively thick exoskeleton.

25

26

 

xofifiu coummemoxm
xmo3 HmEOumwmm

m Hmcmwomahflo .umasoo
ucomn<

uaomn<

muoxoOm Hmccoucm m>onm

wawuumma .owoflun HmEo
numoahs Eouw wcwumcwwwuo

omcmwumom wmuomHMCH

mama uuozm

mGOMDMHdoHuHm “madnwvama
uofiuoucm o>onm mfioumwmoEEH

GOuonxmoxo Mowau hfiuwmm
nmfisoo

chowooamfio .wmafimmc ha
unmoao udn xmms HmEOumHam
ucomoum

uammmum

momma Hmccmucm um

magnomuum .oumoflaoc w awnH

cmEmuom
Hmuwawooo mo ocfim nonuwm

mvou sumo

iHHmw nmwcodm hum> wcoq

mcowumHSQfluum Hmfisnflccms
nowumuam m>onm mfioumfivoEEH

acuoamxmoxm Mowca
xmm3iu
HmEoumHam .wconumuuumHsoo

among a “poem

uaomoum

momma Hmccwuam mo
cmumuma wcwuummawuuwaouum

cosmnom Hmuwawooo mo
mbflm umfiuwo so @ SoHom

cocoa
-ume cam ommn um woman

mcowumHsoHuum pad:
unawamE Hownmuam onu wCH
-GHOM d o>onw hfioumwvoEEH

mHzmzzoo mmmHo

mZOHHOMAmZH

mszm

mumHmm A<HMOHZMH

mzm< A<mmon

mzm< MOHMMHZ< mo
ZOHHmmwzH m<mm

mzm< MOHMHHZ<
mmH ho mm<mm

de
mmH ho ZOHH<UOA

 

Ahudumv
“cumusuhaom mnawooaom
omuwcwooHom

 

Aaommmuov mxmamumm

 

acoumcumn mscmomocflvhmm
mmvwcowuasuoummo

ommE£m<

 

mwfimawEHou momsuuouooum
omcwaauuouooum

 

<MQHOmDMHOHoomm mmfi mo ZOHMAMMm n<mm A<ZMMHZH mmH mo mflMDHUDMHm-:.a mqm<fi

BETHYLOIDEA

Figure 4E and F

The ATP may be at or above the anterior mandibular articula-
tions. The anterior arms are laterally compressed with dorsal
wings or somewhat twisted and insert on either side and/or below the
occipital foramen. Dorsal arms may be vestigial (Trichrysis) or

strong and connecting to the face (Lycogaster). A tentorial bridge

 

is present and bears a spine.
The exceptional feature observed in this group is a ventral
arm branching off just below the dorsal arm on the tentorium of

Pristocera. The arm extends downward only a short distance. The

 

distal end is free. Pristocera has the most well developed example

 

of this type of ventral structure that has been observed.

27

 

umflsoo nucmmnm
nuHmcmwommhfio .HmEoumHQm

ucomoum

haamuucm>omuow cosmuumHm

mEum powumucm
mm mwumfi mm mammocn-
mp0s commouano hfifimumumq

cofimuom
Hmuwaflooo mo mwwm umzuwm

28

mmou mommouano hfiampmumq

mcoflumfinowuum Haasn
-Hccme uowumucm mnu cam
muoxoom Hmccmucm amoBuom

xownu acumaoxwoxo
.Eum ammuov osu mo awwwuo
wnu 3oHon umdn cum3SBov
muommoum Sum Hmuuam> 4

unavoo
.xownuunam50umwmm

vo>uomno uoz

mwcfiz ammuou Saws
woman hauumm d uammoum

mwGwB HMmHou
osu m>onm wcwuoomonm
hfimnmn mam zuwz woman

:oEmuow Hauwmwooo
mo mmwwo HmuoumH HoBOA

Suwaoa muwuco
mzu wcwccsu mewB HMmHOp
owuma nuHB much umbcmfim

mcofiumH:
nowuum umHDnchmE Howumuam
mnu um mumawwHo mmcqmucm

numumeOm Hmccouam u<

unapoo .Hmcmwooahfio
ucmmnmiiHmEoumwmm

ucommum

uammmum

Hmamaumm>

:oEmuom Hauwmflooo onu mo
mcfim umsuwm so a Bofiom

mwou woumw3u umssmEom

Awmwooam mHSu aw 30H
hum> mmccmucmv mumeOm Hma
icouam mo cmuoumfi d Humuon

mHzmzzou MmmHo

mZOHHUMAmZH

MZHmm

mwnHmm A<HMOHZMH

mzm< A<mmon

mzm< mOHMMHZ< mo

ZOHHMMmzH m<mm

m2m< MOHMMHZ¢
mmH mo mm<mm

mH<
NEH mo ZOHH<UOA

 

Uumxosnom
mumHHDQ “mummwowaw
mmcfiamcowfiuH

 

ham
whwmwfihm MHQUOu mem
mmeaasaumm

 

Aumfiuoammmqv
mcmwwuu mflmhunowuH
mmeaeamsuao

 

 

 

<MQHOAMmHmm WEB mo ZOHmAmMm Q<mm A<ZMMHZH MIR mo mMMDHUDMHmuI.oH mqm<H

r19. 4, 1,], W rosae, Cynipoidss:
cm, gleam“ ulnar-tor, "octetmpotdss:
SJ. W gridsng, Bethyloidea.

 

   

FIG. 4

SCOLIOIDEA

Figure 5A and B

The anterior arms may be a stout rod with mesal wings

(Campsomeris) or laterally or dorsoventrally compressed. The ATP

 

are either at or above the anterior mandibular articulations. If
the latter is the case the clypeogenal suture is inflected. Poste-
rior arms meet the back of the head at either side of the occipital
foramen. Dorsal arms are often absent and if present they do not
reach the face.

The tentorial bridge differs from most other Hymenoptera in
that it is usually a broad plate rather than a thin rod. A Spine is
present. Inflections are generally well developed and the lower
face is additionally reinforced as the mandibles are set in separate

sockets.

30

31

 

oumumaom
mumeOm amasaflpcme
.COOonxmoxo xoflnu >um>

wcwxoma hfiownmfi
mcowuooamcfl Hmaowomahao
a .HmEOumwmo .umHSUO

wcwucfiom cumBCBOQ

mauofluoucm voucfloa .vmoum

ucmmn<

:oEmHOm
Haufimwooo mo mcwm umfiuwm

swwume
Hmuuam> so wcw3 HammE
mwumH cuHB mwou uSOum

coflumHSUHuum
umfisnflvcme newumucm m>onm
¢,mmmn Hmccoucm onmm

mumumamm
muonOm umfisnwwcmz

amazoo
d Hmcowomamao HmEoumwdm

ucmmmum

ucomoum

unmmn<

cosmuom
Hmuwaflooo mo scam umsuflm

won cchmE LuHB
usn commwumEoo hfiamuoumq

mGOwumfisoHuum umHanUamE
nowumucm o>onm a muoxUOm
Hmccmucm mo mmuouwa

mumummom
muoxUOm umasnwwame
.coumaoxmoxo onnH

omacoucm

@ mH< com3umn unmmCH
mmccmucm mm ucmmnm HmEOum
uwmo .umHsoo .Hmcmwomtho

mwwflun HmflHOucmu
mo xmam um uammoum

MOMumucm xomm nuw3 mumam
smaswcmwuu m mm ucomopm

mumumcmwoa

cmEmHOW Hauwawooo
ozu mo scam Moguam

uDODm
.UmcmuumHm %Hamuuco>0muoa

mcowumasowuum

smasnfiocme powumucm
mnu mo wmmmE w mumxoom
Hmccoucm wzu mo cmumumq

mHZMZZCU mmmHO

monHUMAMZH

mszm

MUQHMM A<HMOHZMH
mzm< A<mMOQ

m2M< MOHMMHZ< mo
ZOHHmmmZH m<mm

mzm< monmHz<
WEB mo mm<mm

mH<
MflH mo ZOHH¢UOA

 

AmSHoHunmmv

 

mumHSomEHuwmmm.mHuoEommEmo
omwwwaoom

Amswofiunmmv
EduUCHoomdcfinw ESCHNNE
mmeaaaaae

 

 

AmSoMGCHAv
wHHMqubHooo
mm mHkusshmma

omwwaawusz

 

 

 

 

<MQHOHAOUm mmH mo ZOHMAMMm m<mm A<ZMMHZH mmB mo mmMDHUDMHmII.HH mqm<H

FORMICOIDEA

Figure 5C and D

More structural uniformity was observed in the ants than in any

other superfamily. Five species in addition to Camponotus (see Table

 

12) were dissected and their internal head structure was found to be

remarkably similar. The species examined were Lasius neoniger En.,

 

Formica fusca L., Atta cephalotes (L.), Monomoron pharaonis (Linnaeus)

 

 

 

and Ponera coarctata pennsylvanica (Buckl.).

 

Relatively slender anterior arms bearing narrow wings dorsally
span the length of the head from either side of the occipital foramen
to the anterior mandibular articulations. The anterior arms are
joined near the occipital foramen by the tentorial bridge which bears
a spine. Dorsal arms were not observed in any of the specimens
examined.

The outstanding feature of the internal head skeleton of the
ants, not observed in the other Hymenoptera, is a deeply inflected
gular suture. This longitudinal support probably adds much to the

overall strength of the head capsule.

32

33

 

HmEOumHmo.aomw umst «cowuomfimcw wcouum nuflS usn HHmEm momm monHomqmzH

popcmfim zum> cam wcoq MZHmm

ucfloa umcu um umSuowOD mmoHo mum mEum mm uHOLm monHmm A<HMOHZMH

ucomn< mzm< A<mmom

:mEmu0m Hmuwmwooo ecu «0 mcfim Moguflm mzm< MOHMMHZ¢ mo ZOHHMMmzH m<mm

wawB wcoH Bouumc suHB mvou umvcmHm sz< MOHmMHz< WEB mo mm<mm

wGOwumasoHuum umflsnwccme “Owumucm onu m>onm mfioumwvoEEH mH< mmH mo ZOHH<UOA

 

 

ummoon wsoficm>mwmccwm msuocomEmo
omcHoHEuom

 

 

<MQHOUHZmom mmH mo ZOHMAMMm 94m: A<ZMMHZH mmH mo mmMDHUDMHmun.NH mum<H

VESPOIDEA

Figure 5E and F

The internal supporting structures in the head of the Vespoidea
are more numerous and more elaborately developed than most Hymenoptera.

The anterior arms are roughly the shape of a broad, flat ribbon
which has been twisted 180 degrees. They meet the face at the anterior
tentorial pits which are long and slitlike and Occupy most of the
clypeogenal suture and part of the epistomal suture. The anterior arms
extend diagonally upward from the ATP to meet the back of the head on
either side of the occipital foramen.

Extending mesally and laterally along much of the length of the
anterior arms are flattened wings which serve as enlarged areas for
muscle attachment.

Dorsally, and near the occipital foramen, the anterior arms

give rise to dorsal arms. In Vespula and Arachnophroctonus these arms

 

are very weak and delicate and do not reach the region of the antennal

sockets. Dorsal arms are absent in Hypodynerus.

 

The posterior arms extend upward and mesally and cross the
occipital foramen to form the tentorial bridge. A spine extends
anteriorly and downwardly from the center of the bridge.

The epistomal suture, where it is congruent with the anterior
arms, is inflected. The clypeogenal suture is strongly inflected and

34

35

connects the tentorium to the anterior mandibular articulation. In
Vespula, a unique sclerotized bar, the strengthening inflection to

the posterior mandibular articulation, originates at the lower end of
the facial insertion of the anterior arms and connects to the tentorium
at the posterior mandibular articulation. Strengthening inflections
are also found along the malar suture as well as the lower, lateral
edges of the head capsule. The eyes are surrounded with a deep

ocular inflection as they are in most Hymenoptera.

36

 

HmEOumHmm

mumowaoc huo>

ucomoum

Lehmaumm>

:mEmuow
Hmuflmflooo mo wwwm Honuwm

mfiwcwe mnu
SH meHB HmmmE HHmEm nowB

cmumw3u cam vocmuumam

cowumdsowuum umHsnwbcmE
uofiumucm msu mo UnmmE
@ o>onm muHHm Hmucowwuom

msmd%fio w woke owumA

aoflumasowuuw
amasnwosme nowuoumom ou
mH< muomccoo was noccmflm
.uuonm Hmcmwooahao

.xmoB HmEOumHmo .umHSUO

ucmmwum

can“--emnoum manwam

oxwawmounuiumumowfimc hum>

mammsomfi .M mxfla huo>

zaamwme mwcfiz mocammxo
mm: mam: uofiuoumom umsu

uaooxm mammnoma .m mqu

mHSuSm Hmsmw
-omakao mo suwcma mufiucm

mama%fio @ moms owuma

uuosw Hmcmw
nooamfio .HmEOuwfimm .Hmaaoo

oumoflawc mum>

mumo
-Hame Sam vacuum sanwam

Sammn<

cmEmuom Hmuwawooo mo maww
name Hmumuma cam Ho3OH do
mafisomuum .mmmn um woman

hfiuowu
noumom :Hmwm wawvcmmxm
a ofimuwe osu ou wcH30H
-umc mH¢ mnu um command
-Eoo %HHmuoumH @ vmoum

ouzuam Hmaow
noomhfio mo zuwcmfi muwuam

mHzmzzoo mmmHO

mZOHHDMAmZH

mszm

monHmm A<HMOHZMH

mzm< A<mmoa

mzm< MOHMMHZ<

mo ZOHHmmmZH m<mm

m2m< MOHMHHZ<

mmH mo mm<mm

mH<
mmH mo ZOHH<UOA.

 

Amxcmmv mwfimcflwume
m3¢0uooundeSUmp<
mmeaHHQEOL

 

mammncaq
wumfidome wanmmo>
mmcflmmw>

 

AuowumHmamAv
wwmozomH msuochoomhm
mmcwmmo>

 

 

 

«mnHommmS ME mo ZOHMAMMm 9am AégHZH MPH mo mmgHUDMHmiu.mH mama”?

Pig. 5, 1,3, gunmen“ flaringllts, 80011016“;
6,9, M Ennglvnggcus, Formicoidea:
8.9, 265321. mg Ista, Vespoidea.

 

 

SPHECOIDEA

Figure 6A and B

The tentorium of the Sphecoidea is similar in many respects to
the Vespoidea. The anterior arms are variously flattened and twisted.
The rear insertion is on either side of and/or below the occipital
foramen. Dorsal arms if present appear as vestiges and never extend
as far as the face. In every specimen examined the tentorial bridge
was present and bore a spine. Facial inflections are usually well
developed.

A major difference was noted in the head capsule of Cercerus
and Ectemnius. In these species the mandibular sockets were separate
from the main mouth opening. Ectemnius is also unusual in that the
anterior arms are fused with the mesal ocular inflection. The eyes
of Ectemnius occupy much of the face and are very close together.

The very deep mesal ocular inflection doubtless adds a great deal of

strength to the head capsule.

38

 

39

 

 

wcflucfiom Unm353om

macaw
Loon Eouw mfiuoflumucm d
maammmE wcficcmuxo upOQdSm
mxHH wow wawcmnuwcouum

m suaS Gonna“ vmoun <

momm
wcflfiommu uo: w uponm hum>
usn mEum nowumucm Eoum
wcflcsuuoum mamdoowmmcoo

coEmuow
HmUHmHooo mo mwfim umnuflm

zauowumucm coflu
nomeCw unasoo Ou wouoo:
Icoo .cmmmmuano mfiamuoumq

who
mo umcuoo HmmmE um3oH u<

ucommum

ucomoum

momma mo cowumowc
-CH How unmoxo ucmmn<

:mEmuow Hauw
unwooo mo mumcuoo HmBOA

uozouuma uoozm
Hmucouwuo: mam umww3
mum mwcfiz Hands uaoo
uxm mmwwmamw Ou umeEHm

ceauoHso ou “maaeam

ucmmmum

ucommum

Hmawaumm>

cmEmuOM Hmuwawooo Bonm

mwcwz

HmmmE mm wumBuow wawwcouxo
m hauoflumumom mEum mag
uuomccoo uomsm Haucouwuon
Sago .hfiuoflumucm wawcmvHB
can commmHQEoo kHHmuoqu

coflumH56wuum umfidnflwcme
wowpwucm cu mmmn Hancoucm
Eouw wcwccsu muflflm wcoq

mZHmm

mmemm A<HMOHZMH

mzm< A<mmoo

mzm< MOHMMHZ¢ mo
ZOHHMMmZH m<mm

mzm< MOHMMHZ<
mmH mo mm<mm

mH¢
mmH mo ZOHH<UOH

 

 

Azufismv mwumflswcwm
Aounmuoouzmoqv mSHGEwuom
mmcwoofimm

 

Ammmv
mwfimuucm> mouuhowm
mmcwomfimm

 

 

msomccwq
seasonsow am.cofiuofizo
mmvwomnmm

 

 

<mmHoommmm mmH mo ZOqumMm Q<mm A<ZMMHZH mmH mo mMMDHUDMHmuu.¢H mAm<H

4O

 

mumumaom
muoxoow HmHanvcmz

mmhm mfiu

an comm osu mo Eouuon msu
ou cmcsouo mum mmccmucm a
mH< mm umoH umoEHm ousuzm
Hmmeommmfio B HmEoumHao
.Hmwuon Hmmma co owuma
mum> :ofiuooamcfl “wadoo

umfisoo .HmEoumHam

umasoo
.momm co swwniuHmEoumHam

mHzmzzoo mmmfio

mZOHHUMAmZH

41

manusm Hmcmwooazao mo «mum

Ga cocoxownu acumamxmoxo .oGHH unwwmuum
m CH mmccoucm a mH< muooccoo HmEOum
imam .mvfim HummE co mwuma hum>uuHmHSUO

HHmEm

pammmum

oomm ou hmB
mo M\H mcou xmm3 mm wCMvcmuxmuufimflwwumm>

CoEmuow Hmuwawooo mo mwwm Hosuflm

hauofiuwucm commmuQEoo maamuucm>omuoc aha
-uofiumumoa commmpano mfiamumumfi .vmumflse

mcoflumHSUHuum pmfisnwvcms HoHHmucm o>on<

HmEoumHaw @ awasoo

wCHucflom vamBCBOwunmumoHHmm huw>
ucomoum

mem

powumucm mo mcwm ammuoc so momma Eonw
mafiwcmuxo mmwflumm> mfinmuaoopmm mfimumm
coEmuom Hauflmwooo mo ocwm umzuwm
mauowuoumoa

mxHH cow muoE .hauoHumucm mnoH

Hamuoc fiuflz 6 commmuano hfiamumumq
umoE HoBOH muse House

. v omq um a mxaauaam scaumasoauum
awasnwpcms uoflpmuam m>onw cam puma:

mZOHHUMAmzH

mszm

MOQHMm A<HMOHZMH

mzm< A<mmon
mzm< MOHMMHZ< mo
ZOHHmmmZH m<mm

m2m¢ MOHmez<
mmH mo mm<mm

mH<
mmH mo ZOHH¢UOA

 

 

mam maumcwwumEm mDHmnhxo
mmwfiomnmm

 

%mm mauwaom msnucmeLm
mmvwoonmm

 

<moHoommmm mmfi mo ZOHMAMMm Q<mm A<ZMMHZH HEB mo mWMDHUDMHmII.mH mam<H

42

 

Hmflsoo .HmEoumwam
ucomoum
ucommum

uammn<

cwEmuom Hmuwmwooo scams @ mUHm Mosuflm

wwcmuumfim w Umumflzu mamdoHum>

mcowumHSUHuum umannwwcme “Owuoucm
o mmmn Hmccouam cmm3uon V omq u<

oHSmamo mam: mo Ecuuon um mwcwcoao m
umanoo .wcouum %HufimmuuHmEoumHam
wcwucfloa mumBEBOmunwumomeQ

ucmmmum

ucmmn<

mwcwwn HmEOumom%£ ou ome
d GmEmpom Hmuwawooo mo scam nonuwm

omcmwumom wouomfimcw ou

couooacoo .hfiuoHumuwoa ummwmuano ha
-Hmowuuo> .mauowumucm vmcouumam hfiamuu
ucm>omuownnmwawz flames owumfiuuonano

coHu
umHSUMuHm unasnflwcme “Owuoucm mfiu Eoum
hfifimmoE mocmuxm £UH£3 mafia Hmucouwuoa ¢

mHZMZZCU mmmHO

mZOHHUmquH

mszm

MDQHMm A<HMOHZMH

mzm< A<mmon

mzm< mOHMMHz< mo
ZOHHMMmZH m<mm

mzm< MOHMMHZ<
mmH mo mm<mm

mH<
mmH mo ZOHH<UOA

 

 

LuHEm mcmumflv mouwnomH
mmvfiomsam

 

zuHEm mcoomouwwc msuooumo
omcfiomsam

 

APOIDEA

Figure 6C and D

In all the bees examined the anterior tentorial pits are con-
nected to the anterior mandibular articulations by inflected clypeo-
genal sutures. The anterior arms vary from relatively unmodified
rods to flattened or twisted bands. Often they are fused for a large
part of their length with inflected postgenae. The anterior arms
meet the back of the head on either side and below the occipital
foramen.

Dorsal arms are often present but only as vestiges that do not
meet the face. The posterior arms join to form a bridge and a spine
is always present. Most inflections are well developed and the
mandibular sockets may be nearly separate due to deeply inflected

postgenae.

43

44

 

ummoHoco hfiumoc
muoxoOm Hmasnwbcmz

omcmwumom couoonCH

ma uoE HmcmwOucoum umHDoo
.Hmcmwommhao .HmEoumwmm
ucmmmum

cflcusuucmmmum

Hmamaumm>

amEmuom

Hmuwawooo mo mcwm yoguwm
aoHuooncw

Hmcowumoa cuw3 vowsm
mmMSuSm

Hmcmwoucoum @ HmEoumHao
Hmcmwomahao mo :0wuoc3h

mumumdom
mumxoOm smasnwwcmz

Hmcowomm%ao .Hmcmwumom
mumowamv w cfisfi
oumowamw @ aflnH

uaomn<

CmEmHom
Hmuwawooo mo owwm Hmnuwm

omaowumom
vmuooawcw cuflS wmmsm
w vmaouumfim hamsowum>

wcflcoao umHDAchmE
d momma Hmccoucm amo3uom

oumummmm
muoxUOm unannwwsmz

Hmsoumflao a Hmcowoomhao
.Hmcowumom “HmHDUO
ucommum

ucommum

ucmmn<

:oEmuom Hmuwawooo
Bofion w mofim umsuwm

moon commoudEoo hafimuoumq

uoxoOm Hmcaoucm 30H
non zHustHm paw wmnmumq

mHZHZZOO mmmHo

monHUmAmzH
mszm

MUQHMm A<HMOHZMH
m2M< A¢mmom

m2m< MOHMMHZ< mo

ZOHHMMmZH m<mm

mzm< MOHMMHZ<
mmH mo mm<mm

MH<
mmH mo ZOHH<UOA

 

Ea
abomououmn mHEoz

mmeauuaamm

 

mmsosvcmm
EswcmuHEvm mauoHHMwQ

 

nuHEm
wHEuomwcmuccm mammoHHHmo

omcwamuwc<

 

mmeauoaam:

IIIII III II

<mnHom< NEH mo ZCHMAMMm Q<mm A<zmmHzH mmH mo mMMDHODMHmn-.©H mqm¢H

45

 

mumummmm
haummc mumxoOm umfisawvcmz

Hmcmwomamflo

B HmEODmHamuuumHSUO
uaomoum

ucmmoum

Hmawaumm>

mcofiuomfimafl amcmwumom nuw3
M\N Howuoumoa Mom vmmsm

BmmmoumEoo kHHm

numumH mum >o£u maowuoofimcH
Hmmeumoa mo omum muonz

mmumHHoo :H m4

wmuowHMCH mamoow
mmcmwumom .Hmcmwomamao
B HmEoumwmo .udeoo
uaommum

ucommum

Hmamaumm>

cmEmuom

Hmuwmwooo mo swam Hmcuwm

mH¢ Mama wmmmoumsoo
haamumumfi .mvou wwamuumfim

mouoHHoo CH m¢

oumumaom
hfiummc muoxUOm awasnfiwcmz

umaaoo B
Hmcmwooakao .HmEoumHam
udmmmum

mumoflaop B newcofim
Hmamaumo>

cmEmHom Hmuwmwooo
BoHon B owwm Honuwm
wmcmuumaw

B wmumw3u hamsofium>
muwam

mum mH< .mcowumfisowuum

umHnnHUamE uofluoucm B
mumeOm Hancousm amoSuom

mHzmzzoo mmmHo

mZOHHUmAmzH
mszm

MOQHmm A<HMOHZMH
mzm< A¢mmOQ

mzm< MOHMMHZ< mo

ZOHHMMmZH m<mm

mZM¢ MOHMMHZ¢
mmfi mo mm<mm

mH<
mmH mo ZOHH<UOA

 

acmunonom
figucmwamn macuwa<
omvwcounc<

II

 

<mmHom< HEB mo

ham
msumoon mammHhm
mmkumaaoo

 

couumm

 

msumEum manadawm mmuoHHoo
omwwuoaaoo

II
II

ZOHMAmMm gum A<ZMMHZH ME ho mmMDHUDMHmII§H magma.

46

 

Hmaowumom
.HmEoumHam .Hmcmwomdhfio

ucmmoum

ucmmoum

momm cu wcHuooccoo uoa usn
magnomou hfinmociuxmmz hum>

cofiwu0m
Hmuwmflooo mo mvflw Hmsuwm

mwom

mCOwumadowuum
umflsnwmcme HoHHmucm o>on<

vomoHocm haumoa
muoxUOm umfisnwwcmz

oaasomwoz CH m4
ucommum
ucommum

umm mm oufldv wavcouxo
uoc unn Umewmwoz aw m<

amEmuom Hmuwmwooo mo
owwm nosufio :o B BoHom

mocmuumam mamsowum>
unwamn Hammn pom Bomsm

maanomwmz as m<

Hmaowumom
.Hmcmwoucoum .Hmcmwommhau
.HmEoumwmm annadoo

gas“ a waoa
ucmmmnm

magnomuum
uo: usn muonOm Hmccmucw
ou wacaouxo .CHLu muo>

:oEmHom 3o~mn wmmsm mum
mEu< .cmsmuom Hmuflmwooo
Bofion Bum swam umcuwm

wmcouumHm hamDOwum>

mmHDuSm
HmaowOucoum Bum .HmEOumHao
Hmcowooa%fio mo unduocsn

um uoxUOm Hmccmuam 30Hom

mHZMZZOU mmmHO

mZOHHumAmZH

mszm

MUQHmm A<HMOHZMH

mzm< A<mmom

sz< MOHMMHZ< mo

ZOHHmmmzH m<mm

m2m< MOHMMHZ<
mmH mo mm<mm

mH<
mmH mo ZOHH<UOA

 

madman“;
mummwfifime mwam
mmeaa<

 

commono
mumcwumo mowmflumm
mmuaaaaommmz

 

mmm macmEHumH

 

AmsummOSucmnv sawsomwmz
mmeaaanomwgz

 

<moHom< mmH mo ZOHMQmMm Q<mm A<ZMMHZH mmH mo mMMDHUDMHmii.mH mqm<H

Fig. 6. 11,3. Chlorion 3... ichneumon, Sphecoidea:

6,0, hndrena helianthi, Apoidea.

 

 

SUMMARY

Structural support of the hymenopteran head capsule may be
contributed to by inflected postgenae, separate mandibular sockets,
various inflected sutures, and in every case a tentorium. The ten-
torium is of greatest interest in this regard and is commonly composed
of anterior and posterior arms. The anterior arms often bear dorsal
arms.

Some interesting differences in the tentorium appear to be
associated with phylogenetic relationships. The tentorial bridge is
generally better developed in the more advanced Hymenoptera while
dorsal arms are best developed in the more primitive groups. The
symphyta have in most cases lost the posterior arms which usually
form the tentorial bridge in the higher superfamilies. The presence
of a spine, protruding from the juncture of the anterior arms suggests
that the posterior arms are lacking; they may be fused with the anterior
arms. The tentorial bridge does not appear to have great reinforcing
value but it is interesting to notice that the protruding spine is
especially well developed in those Hymenoptera that have mouth parts
well adapted for sucking. The extent of variation of the tentorial
bridge is considerable. It is best developed in the Sphecoidea,
Vespoidea and Apoidea.

The primitive Hymenoptera while often lacking a tentorial
bridge usually have dorsal arms well developed and connected to the

48

49

 

face. All the Symphyta and the four of the more primitive super-
families of the Apocrita show this feature. None of the scolioids,
veSpoids, Sphecoids, apoids, and formicoids examined was found to
have the dorsal arms attached to the face and in many cases dorsal
arms were vestigial or absent. However, elaborate compensatory de-
velopment is observed in these groups in the anterior arms which
are often widely expanded for muscular attachment, fused with inr
flected postgenae, and attached over considerable distances at the
epistomal and/or clypeogenal sutures.

Less complex anterior arms are usually the case in the more
primitive Hymenoptera. Their anterior tentorial pits however are
often located at or very near the anterior mandibular articulations
(Fig. 2C). The separation of the anterior tentorial pits and man-
dibular articulations common in the higher Hymenoptera creates the
need for an auxiliary structure to retain the rigidity against man-
dibular action that was originally provided more or less directly by
the anterior tentorial arms. The author concurs with Bigelow (1954)
that this has been accomplished by the development of clypeogenal
inflections. These form braces between the tentorial arms and the
mandibular articulations. Further bracing is sometimes provided by
an inflected epistomal suture and/or by a ridge around the lower rim
of the head capsule.

These thickened sclerotized areas combined with the tentorium
serve to brace the lower part of the head and allow stresses caused by
biting to be transmitted more evenly to other parts of the head. In-

flections of this kind are usually most pronounced in Hymenoptera

50 I

 

that have powerful mandibles. Mandibular support is sometimes achieved
in other ways. The postgenae may be inflected so deeply that they
connect with the face below the tentorium. In some groups--notably

the Scolioidea the mandibles are enclosed in separate sockets rather
than occupying a large single opening with the other mouthparts.

Enlarged eyes also present a bracing problem especially in the
Scolioidea, VeSpoidea, and Apoidea. Since the eyes are covered with
thinner exoskeletal material they are in a sense a hole in the head
capsule. This weakness in the head capsule is compensated for by a
circular inflection that supports both the eye and the capsule. Those
Species that have very large eyes often have very large ocular in-
flections and in a few cases (Ectemnius for example) the mesal eye
inflections are united with the flattened anterior arms of the ten-
torium for still greater rigidity.

There are many exceptions to the previously described relation-
ships. Similarities in structure often exist between groups that are
widely separated by taxonomists. This perhaps is a result of con-
vergent evolution and the functional necessity for rendering support

and rigidity and support of the head capsule.

BIBLIOGRAPHY

Bigelow, R. S. 1954. Morphology of the face in the Hymenoptera.
Canadian Journ. 2001., 32:378-392, 21 figs.

Du Porte, E. M., and Bigelow, R. S. 1953. The clypeus and the
epistomal suture in Hymenoptera. Canadian Journ. Zool., 31:
20-29, 21 figs.

Hudson, G. B. 1945. A Study of the tentorium in some orthopteroid
Hexapoda. Jour. Ent. Soc. S. Africa, 8:71-90.

. 1947. Studies in the comparative anatomy and systematic
importance of the hexapod tentorium. II. Dermaptera and
Isoptera. Jour. Ent. Soc. S. Africa, 9:99-108.

. 1948. Studies in the comparative and systematic importance
of the hexapod tentorium. III. Odonata and Plecoptera.

Jour. Ent. Soc. S. Africa, 11:39-49.

Matsuda, R. Morphology of the Insect Head. Mem. Amer. Ent. Institute
of Ann Arbor, Michigan. 1965. 334 pp.

Snodgrass, R. E. 1935. Principles of Insect Morphology, 667 pp.,
319 figs. New York and London.

. 1956. Anatomy of the Honeybee. Comstock Publishing
Associates, Ithaca, New York.

51

 

MICHIGAN STATE UNIVERSITY Ll

III III! IJIIIII

31293 306 964

BRARIES
1