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THE



HAY SOCIETY



INSTITUTED MDCCCXLIV.




This volume is issued to the Subscribers to the RAY SOCIETY for
the Year 1889.



LONDON:

MDCCCXC.



A MONOGRAPH



OF THE



BRITISH

PHYTOPHAGOUS HYMENOPTERA,

(TENTHREDO, SIREX AND CYNIPS, Linne.)
VOL. III.



BY

PETER CAMERON.



LONDON;
PRINTED TOR THE RAY SOCIETY.



JklDCCCXC,



LIBRARY

UNIVERSITY OF CALIFORNIA
DAVIS



PRINTED BY ADLABD AND SON, BAliTHOLOMEW CLOSE,



PBEFACE.



IN this volume I have described the remaining three
families of the Tenthredinidse, the Cephidae, Siricidae,
Oryssidse, and the parasitic Cynipidse. The fourth
(and concluding) volume will deal with the inquiline
and gall-making Cynipidaa, and will also contain such
additions and corrections as increased knowledge may
have brought to light during the period the book has
been in course of publication.

It only remains for me to thank my correspondents
for their continued kindness in assisting me with my
work.



SALE, CHESHIRE;
April, 1890.



A MONOGRAPH



OF THE



BEITISH

PHYTOPHAGOUS HYMENOPTERA,

VOL. III.



TENTHREDINID^E.



Tribe CIMBICINA.

Antennae 6 8-jointed, short, the third joint much longer than the
rest, the last, the last two, or the last three forming a well-defined club,
which is clearly separated from the preceding joints. Wings with two
radial and three cubital cellules ; the first cubital receives both or only
one of the recurrent nervures (Amasis). Transverse basal nervure
received considerably before the stigma; the transverse median is
usually received very near to, or is quite joined to it. Posterior wings
with two median cellules. The accessory nervure is continued to the
edge of the wings, and is united to the anal by a short transverse ner-
vure. Head broad and swollen behind, much narrower in front, so
that the eyes are generally placed more in front than at the sides ; the
eyes are small and oval as a rule. Pronotum with a semicircular
emargination on its hind border. Episternum of mesothorax large, and
separated from the mesosternum by a deep groove, which is directed
rather to the front than very obliquely downwards. Prosternum large.
Abdomen broad, rounded behind, its sides acute, the back arched, the
ventral surface flat, or semi- concave. Mandibles large, deeply 2- or
3-dentate. Saw scarcely, if at all, projecting, broad, the apex curved,
round, and the sides bear little dentated bead-like projectings. Patellee
well developed ; spurs often membranous at apex.

The clypeus is either moderately large and the
labium small, as in Cimbex, or it may be small and the
latter larger and moveable, as in Clavellaria. The
mandibles are large, especially in the males of Trichio-

VOL. in. 1



2 TEIBK OIMBIC1NA.

soma and Clavellaria. In the larger species (Cimbex,
Trichiosoma, Clavellaria) the eyes are small, and are
placed well in front, so that the head projects consider-
ably behind them ; in the smaller species (Abia, Amasis,
and the Brazilian genera Pacliylosticta and Plagiocera)
they are longer and reach nearer to the base of the
mandibles, while it is only in Abia and Zarcea that
the head projects behind them. The other genera
have them situated on the side. In the males of Abia
they become nearly confluent at the top of the head.

The thorax is broad and thick ; the sides project
so that they are somewhat broader than at the top,
the mesopleuraB being slightly hollowed, and separated
by a more or less clearly defined border from the
sternal region. The pronotum is almost horizontal in
front, and has the head closely pressed to it ; it has a
well-defined border above, and from this runs an
oblique emargination towards the head, separating the
somewhat projecting spiracular bearing part in front
of the episternum from the upper portion. The form
of the episternum of the mesothorax is characteristic
through the deep groove which separates it from the
mesosternum, as well as from not being so obliquely
situated as in the other saw-flies.

The mesonotum rises gradually from the pronotum
to the scutellum, which is broader than long, rounded
at the top, is raised above the mesonotum, and late-
rally there runs from it to the tegulas a well-marked
ridge. In front there is a deep hollow, while behind
the post-scutellum is almost obliterated, so that it (the
scutellum) presses closely on the metathorax, which is
raised and semicircular in front and slopes from above
downwards, a deep groove being thus formed between
it and the scutellum, the cenchri being placed on the
edge of the ridge so formed.

The first cubital cellule is as long, if not longer, than
the second. The stigma is linear, and in the Euro-
pean genera is not much differentiated from the costa,
but in the Neotropical genus Pachylosticta it is broad,



TRIBE CIMBICINA. 3

long, and projecting. The transverse median nervure
being either united to the transverse basal nervure,
or received quite close to it, is a well-marked pecu-
liarity of the family. So also is the structure of the
accessory nervure in the posterior wings. In no other
European sub-family does it run to the edge of the
wings without being united directly to the anal ner-
vure, nor with the other tribes is it united to the latter
by a cross nervure.

The larvae are twenty-two-footed, cylindrical in
shape, usually greenish in colour, and dusted over
(especially when young) with a white exudation. Over
the spirales are situated orifices, from which are ejected,
often to some distance, a greenish, acid liquid, which
contains chlorophyll.

They are, with one exception (Abia sericea), so far
as is known, attached to trees or bushes, and spin a
double cocoon, either to the branch of the tree on
which they fed, or in the earth. When they quit the
cocoon they do not eat away the one end entirely, but
leave it hanging by one side (see Yol. II, Plate XII,
fig. 5) as a lid.

The tribe must be regarded as a Palaearctic and
Nearctic one, many of the species, indeed, penetrating
very far north (Siberia, Labrador, Hudson's Bay) ;
but, as already mentioned, two genera are found in
Brazil, and species of Cimbex, &c., occur in the West
Indies (Hayti), South America (Brazil, Argentine
Republic;, and in the Old World in Japan and North
India.

This tribe contains the largest and most bulky
species of Tenthredinidde. As above defined, it con-
tains the Palsearctic and Nearctic genera Cimbex,
Trichiosoma, Praia, Clavellaria, Abia, Zar&a, and
Amasis, and the Neotropical genera Pachylosticta and
Plagiocera. The Australian genus Perga is included
in the sub-family by many authors ; but while Perga
has undoubtedly some affinity with the Cimbicina^ it
yet possesses sufficient distinguishing points to warrant



4 SUB-TRIBE CIMBIOTDES.

its being raised to sub-family rank. But whether it
should form a family by itself or one along with
Syzgonia, Laboceras, and Cephalocera (which have also
been placed in the Cimbicina, or at any rate the two
former), the fact of its having the radial cell appendicu-
lated, there being also only one radial cellule, in its
wanting the lanceolate cellule, and having the tibiae
spined, the form of the saw being likewise different,
are sufficient grounds for ejecting both Perga and
Syzgonia (this genus having also these peculiarities)
from the Cimbicina. The American genera Thulia and
Acordulcera are by some authors united to the Cimbi-
cina, but they also may be excluded, as they have only
one radial cellule.

That, however, the Gimbicides are more closely
allied to Perga and Syzgonia than to the Tenthre-
dina, there can, I think, be no doubt; this is shown
by the similarity of the form of the antennae and
thorax and by the neuration, especially of the form of
the accessory nervure in the posterior wings, which is
nearly the same in the three groups, only in Perga,
&c., the accessory nervure is apt to become obliterated
entirely.

We may with Thomson divide the European species
into two sub-tribes the Cimbicides and Abiides.
Pachylosticta and Plagiocera will form another sub-
tribe allied to the latter rather than to the former.



Sub-tribe CIMBICIDES.

Body large (613 lines), hairy or pilose. Lanceolate cellule divided
by a straight cross-nervure ; first cubital cellule receiving both recur-
rent nervures. Mandibles large ; head swollen at the sides, projecting
beyond the eyes, which are small, parallel, and situated well in front.
Ualcana short, thick, membranous at the apex. Patellae well developed,
somewhat membranous. Palpi short, thick, the last three ioints stout
short.

The larvae are well marked with coloured spots or
markings, and are green or blue, or more rarely reddish.



GENUS CIMBEX. 5

They are usually dusted over with a white exudation
and feed on willows, birch or alder.

Synopsis of Species.

1 (2) Blotch large ; labrum small ; clypeus incised, larger than labrum.

Cimbex .

2 (1) Blotch abaent; labrum large; clypeus smaller than it.

3 (4) Posterior coxae widely separated; antennas with five joints before

the club; posterior femora toothed; labrum and clypeus
black. Trichiosoma.

4 (3) Posterior coxae continuous ; antennae with four joints before the

club ; posterior femora simple ; labrum and clypeus white.

Clavellaria.



Genus CIMBEX.

Crabro, Geoff., Hist. Ins., ii, 261 (1762) ; Fourc., E. P., ii, 361,

nee Fab., Auct.
Cimbex, Oliv., Enc. Meth. Ins., iv, 22 (1789).

Blotch large, wide. Clypeus with a very small emargination ; labium
small. Antennae 6-jointed. Posterior coxae widely separated, and with-
out teeth ; anterior more oval, closely continuous.

The antennae are, I consider, six-jointed. The basal
two joints are small, the third is nearly as long as the
succeeding together, the fourth and fifth subequal. The
club is without any trace of segmentation, or there may
be one or even two strictures. Whether these actually
represent joints I am not at all clear. In one or two
specimens I have, the club has every appearance of
being comprised of three joints ; but, on the other hand
(and I think more often than not), the club is usually
quite homogeneous. If the club is to be regarded as
comprised of three joints that would make the antennas
eight- jointed.

The lateral sutures on the vertex are broad and
deep, and they extend round behind the ocelli, where,
however, the suture is not so deep, especially in the
middle. A short, broad, longitudinal suture runs from
it to the ocellus, which is situated in a deep pit. A
suture runs from the lateral ocelli to the antennas.
The front is thick and projects considerably from the



(3 GENUS CIMBEX.

sides. The eyes are placed at the side of this pro-
jecting portion of the head.

The mandibles are large, and strongly built ; the apical
tooth is large, long, and sharp ; there are two sub-
apical teeth. The labium is very nearly equally lobed ;
the first joint of labial palpi is small, half the length
of the second, and not much shorter than the fourth ;
third very nearly as long as the other three together.
Joints one, two, and four of maxillary palpi are sub-
equal in length ; the third is as long as these three
together, fifth longer than sixth, and nearly as long as
the third.

The first radial cellule is longer than the second ; they
are long compared to the breadth. The transverse
radial nervure is a little oblique. The first cubital
cellule is long, narrow, of nearly equal width through-
out, and longer than the second, which is considerably
wider than it, especially at the apex. The third cellule
is a little shorter, and wider than the second. The
first recurrent nervure is received in the basal third of
the cellule, and is bullated at the junction with the
cubital. The second is received a very little in front
of the first transverse cubital cellule, and is often inter-
stitial. The transverse median nervure is interstitial
or nearly so.

The legs are of moderate size. The tarsi are longer
than the tibias. The patellae are very well developed,
and somewhat membranous. The metatarsus is short,
but is longer than the second joint, the second, third,
and fourth joints become gradually shorter, the fifth
is longer than the basal ; its claws are strong, curved,
inflated at the base, and either simple, or with a blunt,
ill-developed, subapical tooth. In the $ the coxse are
much larger, thicker, longer, and more widely sepa-
rated ; the metatarsus is covered with long hair on the
underside, and the apex beneath is projected into a
large, blunt tooth. On the inner side the coxae are
hollow, their sides project into a ridge, which on the
posterior side and towards the apical third, curves



GENUS CIMBEX. 7

down in a round curve to the apex, forming a hollow
with a blunt tooth at either end. The ridge on the
other side is much less developed, and there is also a
blunt ridge on the underside of the femora, which are
much thickened. The anterior femora are of the normal
size, and they are also grooved. The coxae are not
enlarged like the two posterior pairs.

The abdomen is a little longer than the head and
thorax; the blotch is very wide, and extends nearly
across the segment ; the segments are nearly of equal
size. The ninth does not project at all on the upper
side. Backwards it does not extend beyond the eighth,
the saw does not project beyond the apex of the
abdomen.

The form of the saw and back piece is quite peculiar,
being rounded and curved at the apex, not brought to
a sharp point as with the other saw-flies, and they are
further distinguished by having along the edge little
projecting bead-like points.

The insects belonging to this genus are the largest
of all the TentlirediniddB. They are very variable in
coloration, and this has led, on the one hand, to many
so-called species being made out of the various forms,
and, on the other, to all the forms being united into
one species, as was done by Klug, who placed them
together under the name of G. variabilis. The obser-
vations of Brischke, Zaddach, and Van Vollenhoven,
however, have shown conclusively that there are at
least four, if not five, good European species of Cimbex,
s. sir. Undoubtedly the most satisfactory way of
discriminating the species is by rearing them from the
larvas. Failing this crucial test, it is not always an
easy matter to separate the perfect forms. In colour
they vary exceedingly ; the thickness, texture, and
colour of the hair vary ; the form of the antennae varies,
especially in their comparative length and in the shape
of the club ; the position of the nervures fluctuates :
thus the second recurrent nervure is found in the second
cellule, in the third, and is interstitial in all the species.



8 GENUS CIMBEX.

One species (0. sylvarum) is usually distinguished by
having a fuscous fascia in the first discoidal cellule,
and the edges of the wings are also fuscous, while
usually C. lutea is distinguished by its wings wanting
entirely these fuscous clouds ; but I have seen speci-
mens of sylvarum with the wings completely hyaline,
and of lutea with faint indications of the fuscous tint
along the edge and at the discoidal cellule. I thought
once (like Zaddach, loc. cit., p. 243) that the form of
the scutellum would give a good specific character, but
soon found that this also varied, especially with bred
specimens. Then the posterior coxas and femora vary
in length and thickness in the males. In some bred
specimens I have examined they are not much longer
or thicker than the middle pair, while with caught
specimens (of nearly the same size) they are more
than one half longer and thicker. Nor is the variation
in the size of the coxse and femora confined to bred
examples. The males, too, vary very much in size.
Thus I have one 3 of C. lutea which is 17 lines in
length ; the posterior femora are 4 lines long, and
nearly 2 lines broad in the middle ; another is 8^ lines
long, and the hind femora 2J lines long.

Synopsis of Species.

1 (2) Clypeus and pronotum clear yellow, wings yellowish, the fore

half fuscous throughout ; mesonotum and base of abdomen
punctured. Humeralis.

2 (1) Clypeus and pronotum reddish-yellow or black, wings not fuscous

throughout in front ; mesonotum not punctured.

3 (4) Thorax, femora, the base, sides in front, and lower side of abdo-

men, violaceous. <$ Apex of abdomen black or dull brownish,
and with a violet iridescence. Connata.

Thorax, femora, and base of abdomen not violet.

5 (6) Pubescence on head, thorax and base of abdomen longish, black,
or dark fuscous ; wings with a fuscous fascia in the basal
cellule, and a fuscous border at apex. Head and thorax

A M -D v rarely yell W ' Sylvarum.

t> (5) .Pubescence on head, thorax and base of abdomen woolly, close,
thick, griseous, pale, or yellowish ; wings not marked with
fuscous; head, thorax, and abdomen for the greater part,



OIMBEX SYLVARUM.



1. ClMBEX SYLVABUM.

Vol. II, PI. V, fig. 1, ? ; la, Head ; 1 b, Antenna ; 1 c,
Tarsus. Vol. II, PL XII, fig. 8, Larva.

Tenthredo sylvarum, Fab., E. S., ii, 105, 4; Pz., F. G., Heft 88,

pi. xvi.
Cimbex sylvarum, Fab., S. P., 16, 4; Voll., Tijd. Ent., xriii, 33,

pi. iii.
Tenthredo femorata, Pz., 1. c., Heft 26, pi. xx.

tristis, Fab., Iter. Norw., 334 ; E. S., ii, 106, 7.
Cimbex tristis, Fab., S. P., 17, 7.

varians, Leach, Z. M., iii, 105 ; Ste., 111., vii, 6, 2.

europ&a, Leach, Z. M., iii, 105, 4.

femorata, $ , Fall., Acta Holm., 191, 3 ; Mon., 8, 2 ;

Lep., Mon., 31, 83; F. Fr., Hym., 5, 7 ;
Drewsen, Ann. Ent. Fr., iv, 169 (1835) ;
Ste., 111., vii, 6, 1.

variabilis, var. femorata, Klug, Berl. Mag., 1, 78 ; Htg.,

Blattw., 6, 3.

biguetina, Lep., Ann. Soc. Ent. Fr., ii, 455.

betulae, Br. and Zad., Schr., Ges. Konig., ii, 233 and

249, pi. ii, f. 1 (lar.).

fagi, Br. and Zad., 1. c., 233, 251.

lutea, Thorns., Hym. So., i, 19, 1.

siberica, Kirby, List of Hym., i, 4, pi. 1, f . 1, $ , 387 ;

pi. xvi, f. 3, J.

Black ; antennae and tarsi luteous, body covered with a black or
fuscous, longish pubescence ; wings hyaline, a blotch along the trans-
verse basal nervure, and the outer margin fuscous.

Length 7 13| lines.

Ab. a. Black; antennae and tarsi luteous (tristis).

b. Black ; antennae and tarsi luteous, the three or
four middle segments of the abdomen red. ? and $
(sylvarum).

c. As in b, but abdomen entirely red $ , rarely ? .

d. Black ; antennae, tibiae and tarsi luteous, the three
or four middle segments for the greater part pallid
testaceous, or more rarely the middle segments are
entirely pale testaceous (varians, biguetina, Lep.).

e. The antennas, the head, except the vertex, pro-
notum, the fore part of mesopleurae, the middle lobes
of mesonotum at the sides, scutellum, legs, and abdo-
men, reddish-yellow ; wings yellowish ; the pubescence
is shorter and paler than usual.

This is the most variable and commonest of the



10 CIMBEX SYLVARUM.

species of Cimbex. The variations in the coloration
are very numerous in both sexes. Commencing with
quite black specimens save the antennae and tarsi, we
meet with specimens having one yellow band on the
abdomen, then with specimens with two or three bands,
which lead into specimens with the middle of the abdo-
men entirely yellow, the tibiae being also yellow, and
from this we reach the extreme yellowish form de-
scribed above as Ab. e. We find the same variations
with the red banded forms.

The larva feeds on birch, and is found from July to
September. Its head is pale yellow, granular, and
with black eye-spots, the body is green, more or less
yellowish at the skin folds and along the back, where
there is a black stripe, which is bluish along the centre,
and is widest towards the middle of the body, it being
very narrow along either end. The skin is wrinkled,
especially on the sides, which are beset with numerous
white warts, particularly over the legs. The feet are
white, with brownish claws ; the spiracles black, longer
than broad, and broader below than above ; they arise
from a raised part of the skin.

When young the larva is greenish-white, dusted over
with white powder. It wants the black dorsal stripe
entirely.

Brischke and Zaddach (1. c., p. 237, pi. ii, fig. 2)
describe and figure a larva which was found by Drew-
sen and by themselves on beech ; this is described as
being the largest of all the Cimbex larvae. The ground
colour of the body is a beautiful bluish-green, the
dorsal stripe is clear blue or violet ; the head is larger
and more cubital than with sylvarum, and the white
tubercles are smaller and more pointed. According
to Brischke the characters presented by this larva are
constant, and if that be so the chances are that it per-
tains to a good species ; but unfortunately Drewsen
and Brischke and Zaddach bred only males, which
cannot be separated apparently from G. sylvarum, and
like the males of that species would seem to be very



CIMBEX CONNATA. 11

variable. The above-named German authors name
the beech-feeding form C. fagi.

The following parasites have been reported to feed
on the larvae of C. luteasmd C. sylvarum : Campoplex
argentatus, Rtz. ; G. holosericeus, Rtz. ; C. pubescens,
Rtz. ; Cryptus cimbicis, Rtz. ; C. incubitor, Gr. ; Hemi-
teles dispar, Rtz. ; Mesochorus cimbicis, Rtz. ; M.
splendidulus, Gr. ; Mesoleptus rufus, Gr. ; Paniscus
glaucopterus, L. ; P. testaceus, Gr. ; Pezomachus cur-
sitans, Gr. ; Tryphon mesoxanthus, Gr. ; T. rufus,
Gr. ; T. sorbi, Sax. ; Monodontomerus obsoletus, Fab.

The species is of universal distribution in Britain,
the flies appearing in June.

Continental distribution : General in Europe, also
in Siberia.



2. CIMBEX CONNATA.

Tenthredo connata, Schrank, Beitr. z. Naturg., 83 (1776).
Crabro maculatus, Fourc., E. P., ii, 361, 2.
Tenthredo montana, Pz., F. G., Heft 84, pi. xii.

femorata, De Geer, Mem., ii, 2, 943.

Cimbex decemmaculata, Leach, Z. M., iii, 106; Curtis, B. E., i,
pi. xli; Ste., 111., vii, 7,4.

ornata, Lep., Mon., 28, 77 ; F. Fr., Hym., 4, pi. i, f. 2.

maculata, Ste., 111., vii, 8, 7.

connata, Voll., Tijd. Ent., vii, 50, pis. i and ii; Br. and
Zad., Schr. Ges. Konig., vi, 254, pi. ii,
f. 6 (lar.); Andre, Species, i, 26; Cat.,
1*2.

pallida, Ste., 111., vii, 7, 3, teste Kirby, List of Hym., i, 2.

violascens, Thoms., Hym. Sc., i, 20, $ .

Humboldtii, Ratz., Forst., Ins., iii, 135, 46.

Fuscous-violaceous ; the head, pronotum, pleurae, tibiae, and tarsi,
brownish-testaceous, coxae and femora violaceous; abdomen bright
luteous, the basal two segments entirely, the third broadly in the
middle, apical segments at the sides, and the greater part of the ventral
surface, violaceous. Antenna} luteous. Head, thorax, and base of abdo-
men covered with a griseous pubescence, which is darker on the meta-
thorax. Wings hyaline, more or less spotted with fuscous at base,
middle, and apex.

The ( is violet-black, the apex of abdomen dull fuscous, antennae and
tarsi luteous, tibiae brownish ; head, pronotum, and pleura dull brown.
The wings are coloured as the $ , but have a much more clearly defined
steel-bluish-violet iridescence.

Length 10 12 lines.



12 CIMBEX CONNATA.

With the darker specimens the thorax is almost en-
tirely black, the tibiae are also black or dark fuscous,
and the middle of the abdomen on the back and along
the sides is violaceous, as in G. decemmaculata, Leach ;
with the lighter aberrations the head, pleurae, the
breast in part, pronotum, and the edges of the lobes
of the mesonotum are brownish-testaceous ; the abdo-
men is only violaceous at the base, and on the seventh
and eight segments at the sides; the legs too being
brownish-testaceous, save the femora, which are always
violaceous.

The distinctions between connata and lutea lie in
the darker-coloured thorax and base of the abdomen in
the former, which are always for the greater part
fuscous, for the ground colour, and most distinctly
violaceous, the same being the case with the coxse,
trochanters, and femora ; the wings are darker at the
median cellule and at the apex, while they have also
a more distinctly marked violet iridescence. The pubes-
cence on the thorax and base of abdomen is shorter
and thinner, the spurs are longer and thinner ; gener-
ally too it is a larger insect than lutea.

The larva is of a beautiful clear green colour. The
head is also greenish, with black eye-spots. The dorsal
stripe is bluish-black, with paler spots. It commences
on the first segment, continues to the penultimate, and
is of a uniform breadth throughout. On each side it
is bordered by a yellowish line. Not far from this
yellow line is a roundish black dot ; the spiracles are


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