Peter Cameron.

A monograph of the British phytophagous Hymenoptera .. (Volume 1) online

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Eriocarnpa annulipes, Kl.

Fenusa pygmsea, Kl.
Juniperus communis*

Nematus, sp.

Monoctenus juniperi, Lin. M. obscuratus, H.
Finns, Larix, Abies, $*c.

Lophyrus variegatus, Htg. L. politus, Kl. L.
elongatulus, Kl. L. rufus, Kl. L. socius, Kl.
L. pallidus, Kl. L. virens, Kl. L. hercynisD, H.



40 LIST OF FOOD PLANTS.

Pinus, Larix, Abies (continued).

L. polytoma, H. L. similis, H. L. nemorum,
Fab.

L. pini, L.

Monoctenus juniperi, L. (?)

JSTematus Erichsoni, H. 1ST. insignis, Sax. N.
carinatus, H. N. laricis, H. N. ambiguus,
Fall. N. scutellatus, IT. N. Saxesenii, H. N.
nigriceps, #. N. compressus, H. N. abie-
tum, H.

Lyda erythrocephala, I/. L. stellata, Christ.
L. campestris, L. L. reticulata, L. L. hypo-
trophica, Htg.

Iris. Monophadnus iridis, Kali.
Convallaria multiflora. Phymatocera aterrima, KL
Festuca pratensis. Dolerus gonagra, F. Dolerus

fissus, Htg.

Nematus conductus, Buthe.
Poa aquatica. Selandria sixii, Voll.
Scirpus palustris. Selandria sixii, Voll.
Iriticum vulgare. Cephus pygmaea, L.
Juncus effusus, &c. Dolerus eglanterise, Kl. D.
haematodes, Schr.
Selandria sixii, Voll.

Arundo Phragmites. Cephus arundinis, Girand.
Gar ex acuta, fyc.

Nematus capreas, Pz.
Selandria sixii, Voll.
Pteris aquilina.

Tenthredo balteata, KL
Strongylogaster cingulatus, Fab.
Polystichum Filix-mas.

Strongylogaster delicatulus, Fall.

Str. cingulatus, F.

S. femoralis, Cam.

S. mixtus, Kl. S. Sharpi, Cam.

S. maculatus, Kl.

S. filices, Kl.

Selandria analis, Thorns.



LIST OF FOOD PLANTS.



41



Abstract.





1


&Q


j


S
fc


Cimbicides.


i
I


Lophyrides.


Pinicolina.


!


4

I


^

e

1


Ranunculaceae


3




3


2










8
1
8
1
2
1
1
1
1
5
48
1
4
5
9
1
2
5
3
7
5
3
1
1
3
1
1
3
35
61
14
30*(36)
2
1
4
2
5
6










1










C TUG if 61*38


2


6
1


















Violaceae


















Tiliaceae




fl




















1




















A-COraCeaG




1






















1


















BalsaminesB


1




















Leruniinos8B


2
4
1


1
18




o














Rosaceae


...


11


3


7


...




2


3




GrossulariacesB




1




3














Umbel] iferse


4
















1






5


1






3














1




















Dipsacaceae


1








1












ConipositsB


4


1






















3














Oleacese


4


3


















ScrophulariaceaB


3
1


2
1


















Labiat83




1














Primulaceae




1


















Plantaginaceae


1




















Polygonaceao .




9,




1














Enphorbiaceae


1




















Urticaceae


1




















Ulinacese




1




9














Betulaceas


2

1


7
4
9




19
46
3
11


3
3

1


2

6


...


1


1
1


"i


SalicacesB


Cupuliferae


Conifers










14*


...


5


Iridaceae


1


]
1










Liliacese


















Juncaeeae




1

1


3
















Cyperaceae




1


. I-








Gramineae




1

fi


2












2


Filices































* There are 20 European species, but the larvae of only 14 have
been described.



42 HABITS OF LARV/E.

Unlike the perfect insects the larvae exhibit great
diversity in habits. Many live solitary, others again
are gregarious. Not a few feed exposed in the sun-
shine, while others eat only in the cool of the evening,
or at night. The great majority feed exposed, but
some are internal feeders. Thus, several species of
Nematus and one of Hoplocampa inhabit galls raised by
the parent; a Cryptocampus and Poecilosoma candi-
tatum live boring in the pith of plants ; the Pliyllo-
tomides are leaf miners, and Hoplocampa testudina and
H. brevis live in fruits. Different species of Lyda
roll down leaves, and keep them together with silken
threads; Nematus leucostictus, &c., reside in leaves
folded down by the imago ; Lyda inanita in a case
formed of bits of leaves fastened together, and which
it carries along with it.

Their bodies are mostly cylindrical, but those which
feed on the surface of the leaf are flat ; those which
mine leaves have them very flat, the head triangular
and the legs little developed. Some of them have a
habit of rolling up the body in a spiral, the tail being
in the centre and often upturned. They rest in this
position on the leaves, while others, if they be alarmed,
drop to the ground, and rest there motionless, rolled up
in a ball, until all danger is gone.

The head of the larva is roundish, seldom depressed
in the middle. Sometimes it can be partly retracted
into the over-arching folds of the second segment.
There is a single ocellus on either side. Between them
and the mandibles are short, often microscopic,
antenna, which have three to seven joints, the last
being the number with Lyda, which has them compara-
tively long ; and, unlike their position with the other
genera, they are placed pretty close to the eyes. The
labrum is incised in the middle, the mandibles are
short, thick, horny, and variously toothed. The
maxilla are bilobed, the two lobes being in most cases
closely united, and the inner one is provided with blunt
teeth varying from ten to twenty and upwards in



STKUCTUEE OF LARV.i:. 43

number (PL VI, fig. 3, 3). They are of a fleshy con-
sistency, save with Lophyrus, with which they are
harder and more horny. They are provided with
jointed, thickish palpi, having from three to five joints
(1. c., fig. 3, 1). The labium is thick and fleshy, and
bears short three-jointed palpi, as well as a spinneret,
which may be placed either close to the apex, or not
far from the bottom.

On the thorax are three pairs of jointed legs which
terminate in curved horny claws. There are also, on
the ventral segments, pro- or false legs, which are in
fact mere muscular protuberances. Of these there are
six to eight pairs. In the latter case there will be a
leg for every segment of the body, save the fourth,
which in no case bears appendages. They have never
the clasps found in the pro -legs of Lepidoptera.

In bearing ventral legs, and generally in their mode
of life, Saw-fly larvae have a considerable resemblance
to the caterpillars of Lepidoptera, for which they are
often mistaken. They differ, however, from them in
two important points in having only one ocellus on
either side of the head, while lepidopterous larvae have
several ; and in having a greater number of ventral
legs, ten (or sixteen in all) being the greatest number
with Lepidoptera, while, as stated above, Saw-fly larvae
have from eighteen to twenty-two legs. They differ
too in the position of the legs, the caterpillars never
having a pair on the fifth segment, which always bears
one with the TenthredinidcB, if the abdomen has legs
at all. Lyda has no ventral legs, thereby agreeing
with the Sir ic idee. With most genera, the abdomen
carries on the las-t segment two cerci, which are espe-
cially long with Lyda, while with other species they are
differently coloured from the surrounding parts.

Mostly bare, or at least with the skin wrinkled ; in
other cases, the larvae are covered with tubercles, each
of which ends in a soft or bristly hair, which becomes
in Iloplocampa and Blennocampa converted into a large
branching spine.



44 MEANS OF DEFENCE OF LARVJ1.

It has been shown by recent researches that the
coloration of caterpillars is protective, and that the
coloration is of two kinds. On the one hand it has
been shown that larvae which are readily eaten by
insectivorous animals are always coloured to resemble
their surroundings, and that they conceal themselves as
much as possible; while on the other, it has been
proved that larvae which are inedible through possess-
ing bad secretions, &c., are brightly coloured, and are
often more or less hairy. The same law of coloration
applies to the larvae of the Tenthredinidce ; and the simi-
larity in coloration between them and the caterpillars
(especially with the edible larvae) is not unfrequently
very close. This is more particularly the case with
those which feed on narrow-leaved plants like pines
and grasses.

The larvae possess various means of escaping from
their numerous enemies. A large number escape by
the colour of their bodies harmonising with the sur-
roundings ; thus they are not readily seen, especially
as they are inactive and solitary in habits. Those with
flat bodies feed on the underside of the leaves
(Nematus luteus, Camponiscus, &c.), in which they eat
holes, and many feed only at night. They are all
green, save that the head may bear blackish, or
brownish markings, and, as a rule, the tinge of green
agrees with that of the leaf e. g. Nematus pallescens.
Many of the larvae with cylindrical bodies are attached
to narrow-leaved plants such as grasses, pines, &c.
They also are green like the flat larvae, but they bear,
either on the back or down the sides, white or, more
rarely, pink stripes. The green larvae, which feed on
broad-leaved plants (willows, &c.), eat along the edge
of the leaf, eating in it semicircular indentations, the
form of which they follow with the body, which is kept
closely pressed to the edge. Those larvae are never
hairy, but some of the green flat larvae bear over the
legs, or over the whole body, soft pale hairs, the object
of which seems to be to prevent the body throwing a



MEANS OF DEFENCE OF LARV.1-. 45

shadow on the leaf, and thus leading to the detection
of the larvae. Obviously larvae which live on trees
cannot so readily escape by dropping to the ground as
those attached to low plants. In fact they seldom or
never drop down ; many of them too feed only at night,
but the species of Nematus can defend themselves by
whipping about the abdomen. This is a habit pos-
sessed by all those which feed on the edge of the leaf,
but it is more noticeable with gregarious species like
Croesus septentrionalis. Grass and herbage-feeding
species again feed on the underside of the leaf on broad-
leaved plants, or along the edge of grasses, and they
drop to the ground at once, remaining there motion-
less rolled up in a ball until they think danger is over.
Species of Taxonus and Tenthredo afford examples of
this habit.

The active means of defence consist in ejecting
liquids from lateral pores, or from the mouth, or
in giving off odours from glands (generally abdo-
minal). The Cimbicina possess the first mentioned
peculiarity. The liquid is of an acid nature, and it can
be ejected to a considerable distance and in some
quantity, although after three or four discharges the
supply becomes exhausted for a time. Its principal
use is no doubt against ichneumons, and this, in at
least one case, is the purpose of the liquid ejected from
the mouth. The larva of Perga Lewisii, for instance,
can throw out to some distance a quantity of gummy
matter, the use of which is clearly shown by an
ichneumon having been found with its wings and legs
gummed together by it.

Larvae which give out secretions or fetid odours are
gregarious, several feeding on the same leaf, often
ranged in a row with the bodies stuck out in the air.
They have nearly always bright colours ; the ground
colour, as a rule, is some tinge of green, or even blue,
and the first and last segments are yellow or orange,
while the rest of the body is ornamented with yellow
and black spots which often end in stiff hairs. The



46 COLORATION OF LARV-E.

belly, too, may bear black marks, but only in such cases
where there are glands, which the larva can exsert
at will, and when it has the habit of throwing the
abdomen over the head (as does Croesus) for the double
purpose of exposing the glands, and whipping away
ichneumons. That the larvae can drive away these
insects by means of the abdomen, I have noticed more
than once with Croesus septentrionalis.

Many greenish-coloured larvae give out odours and
secretions, but they differ in habits from those just
described. They are small larvae with flat bodies ;
they feed on the upper side of the leaf, eating only
the cuticle, so that in this way it becomes white. Now,
as these larvae are gregarious, and are not only covered
with secretions, but can also give out bad smells, they
are enabled to surround themselves with a fetid atmos-
phere, which makes their presence as effectually known
as if they had bodies of bright contrasting colours.

A priori we might expect that species which are very
closely related and similarly marked as imagines would
also resemble each other in larvae. But no conclusion
could be more astray from the actual state of the facts.
There are, indeed, some genera and groups in particular
genera in which the larvae and imagines are coloured
and marked alike in the embryonic and developed
states, such as, for instance, with Dineura (so far as
we know), but others which closely resemble each
other in the imago form are utterly dissimilar in the
early one. A striking example of this is found in
Croesus. The larvae of the three British species have
the same forms and the same habits, but as regards
coloration they are utterly distinct. This difference in
coloration is, I think, readily explainable by the larvae
of C. septentrionalis and C. latipes being more active
and more offensive, as is shown by the bad odours they
give out. C. varus, on the contrary, is not quite so
active, and does not use the ventral glands so effec-
tively, but to make up for this it is of the same green
as the alder with only a few slight black lines along the



SYNOPSIS OF LAKV.r.. 47

sides. Now, as is well known, the three images are
very similar, and were considered varieties of one
species before the larvae were known. Again, with
the luteus group of Nematus four of the larvae are flat
and green, while a fifth is cylindrical and reddish.
We find the same diversity with the dermal covering.
In Eriocampa we have slimy larvae, slimeless larvae, and
one covered with a white flaky substance. Hoplocampa
has spiny larvae, smooth colourless larvae living in
fruits, and gall -living larvae. The same diversity
exists in Blennocampa. Some very distinct larvae, indeed,
produce images which can scarcely be distinguished
from each other, e.g. Lophyrus pini and L. similis,
Nematus cadderensis, N.fagi, and N.fulvus, and others.
Contrariwise there are similarly-marked larvae which
give issue to very different flies.

It thus becomes clear that the forms and habits of
larvae are entirely of an adaptive nature, and bear no
relationship with the habits, forms, and affinities of
the perfect insects. Each lives in a different sphere
and has a different food, has to contend against dif-
ferent enemies, and lives in entirely different sur-
roundings from the other. The lives of the flies, too,
are very uniform. Their chief business is to provide
for the continuance of the species ; when that has been
done they either die at once, or live a useless, lazy
existence for a few days, basking in the sunshine.

In his Clams, Dahlbom has given a classification of
the Saw-fly larvae, which Westwood has reproduced
with additions in his Intr.* and Ent. Ann.f for 1862.
The following synopsis is carried out on the same lines,
but in much greater detail.

Synopsis of Larvce.

I. Larva with twenty- two legs.

A. Ejecting from lateral pores a greenish acid liquid,
spinning a double cocoon.

* ii, p. 97. f P. 129.



48 SYNOPSIS OF LAEV.E.

1. Greenish larvce, without markings, covered more
or less (especially when young) with a whitish exuda-
tion. TricMosoma, Clavellaria, Gimbex.

2. Not greenish, with orange and other markings.
Abia, Zarcea.

B. Not ejecting a liquid from lateral pores. Spin-
ning a simple close cocoon, not ejecting a liquid from
the mouth, often giving out a resinous exudation, often
social, never rolling themselves up into a ball, and
always attached to Coniferce or juniper. Lopliyrus,
Monoctenus.

1. Greenish (rarely blackish or brownish) larvse
without definitely arranged spots or markings, some-
times with lines proceeding from the centre of the
back to the sides in the direction of the tail ; generally
lighter on the sides than on the back, resting with the
body rolled up into a ball, often changing colour before
pupating.

a. Pupating in stems, never with lines down the
back ; generally dark green on the back and dirty
white on the sides. Empliytus, Taxonus, Poecilosoma
luteolum.

b. Pupating in the earth, with or without spinning
a cocoon, sometimes with lines arranged down the
back; often ejecting from the mouth a brownish
liquid when alarmed. Tenthredo, Macropkya, Allantux.

c. Larvae for the greater part white and covered with
a whitish exudation.

1. Head reddish-yellow, feeding on oak. Emphytus
serotinus.

ii. Head not reddish, feeding on alder.

The exudation in flakes, covering all the body
spinning a cocoon becoming pale green at last moult.
Eriocampa ovata.

The exudation powdery, not spinning a cocoon,
losing the exudation and becoming pale green before
pupating. Poecilosoma pulveratum.

2. Greenish larvae without regularly arranged stripes
or spots, not resting rolled up into a ball, usually



SYNOPSIS OF LARVJ!. 49

spinning a cocoon mixed with grains of earth, usually
stout, thick- set, sluggish, and generally feeding on the
flat surface of the leaf.

a. Feeding on ferns,
i. Body bare.

Head ochreous, spinning a cocoon. Selandria
anal is.

Head greenish with two blackish spots, not spinning
a cocoon. Strong ylog aster cingulatus.

ii. Body covered with short hairs, head green,
without markings. Strong ylog aster delicatulus.

I. Living in the rolled down leaves of the rose.
]>l nnocampa pusilla.

c. Covered with a slimy secretion, eating only the
upper epidermis.

i. The secretion well developed and of a greenish
or blackish colour, feeding on fruit trees, limes,
birch, or hawthorn. Eriocampa adumbrata, E. annu-
Upes.

ii. The secretion not well developed, and of a yel-
lowish colour, feeding on rose. Eriocampa canince
(fethiops, West.).

d. Feeding on herbaceous plants or grasses, eating
along the edge of the leaf. Small and stumpy in shape.
I lh' nnocampa albipes. Selandria sixii.

e. Feeding in the stems of plants. Poecilosoma
eandidatum,

f. Feeding in the berries of gooseberries, in apples,
and plums. Hoplocampa fulvicornvs, H. testudinea.

3. Greenish larvae covered with branched spines.

<i. Spines green. Blennocampa alchemillce, B. longi-
cornis.

b. Spines blackish. Blennocampa lineolata, B. me-
lititocepliala, Hoplocampa brevis.

4. Blackish larvae without white markings, feeding
on cruciferous plants. Atlialia spinarum, A. glabri-
collis.

5. Black with white dots, feeding on Scuttellaria.
Atlialia scutellarice.

VOL. i. 4



50 SYNOPSIS OF

6. Flat larvse, with triangular heads, and usually
with black plates on thorax, mining the leaves of
plants. Phyllotoma, Fenella, Fenusa, Dineura despecta,
Blennocampa ulmi, Kalt.

II. Larvae with not more than twenty legs.

A. Larvse with greenish- coloured bodies, without
conspicuous markings, or with white, black, or pinkish
continuous lines on back or sides.

a. Flat larvse without dorsal or lateral lines, feeding
on the tipper or lower surface of the leaf.

i. Feeding on upper surface of the leaf, eating only
the upper cuticle, and giving out a nauseous smell.

Body without hairs. Dineura stilata.

Body with fine hairs. Dineura testaceipes, D. Degeeri

ii. Feeding on the lower side of the leaf, eating the
leaf through and through, and not giving out a bad
odour.

1. Onisciform, very broad and flat, the head
retreating and depressed in the centre. Camponiscus
luridiventris .

2. Body slender, head not retreating nor depressed
in the middle. Nematus luteus, N. lilineatus, N. abdo-
minalis.

b. Body cylindrical, rarely feeding on the flat sur-
face of the leaf, without distinct markings, nor with
contrasting colours.

i. Body covered with distinct tubercles each ending
in a hair, feeding on the flat surface in which they eat
large holes.

1. Body entirely green, spinning a close, oval,
brownish, single cocoon in the earth. Nematus pal-
lescens.

2. Body darker coloured on the back and upper half
of the sides than on the lower part, spinning a loose,
irregular, whitish, double cocoon.

Head light brown, body greenish. Cladius padi.
Head and body for the greater part black. Cladius
brullcei.

ii. Body without tubercles or hairs, feeding along



SYNOPSIS OF LAKV-E. 51

the edge of the leaf, with the body kept closely pressed
to it and following its shape. Entirely green or with
dorsal or lateral lines.

1. Body entirely green or green above, with the
lower part of the sides of a paler tint. Nematus rufi-
cornis, N. rumicis, N. fulvipes.

2. Body with black lateral lines. Nematus crassus,
N. miliaris.

3. Body with white lateral or dorsal lines. Nematus
caprece, N. curtispina, N. myosotidis, N. histrio, N.
fallax.

4. Body with pink lines. N. curtispina, N. Berg-
manni.

5. Body with greenish tubercles. N. glutinosce.

B. Bodies marked with black, blue, yellow, or
orange, irregularly-disposed spots and lines; giving
out generally a bad smell, and feeding on the edge of
the leaf with the after part of the body stuck out in
the air. No tubercles or hairs.

a. With distinct ventral glands.

Body black with orange legs. Crcesus latipes.
Body green with faint black lines. Crcesus varus.
Body green with orange markings. Croesus septen-
trionalis.

b. Without distinct ventral glands.

i. Bodies greenish, marked with orange, &c. Ne-
matus fulvus, N. cadderensis, N. pavidus, N. betulce, N.
melanocephalus, N. salicis, N. conjugatus, N. lacteus,
N. maculiger, Cam.

ii. Body for the greater part reddish without any
green.

1. Red with black marks down the back. N. quercus.

2. Red with white marks down the back. An un-
known Nematus on birch.

3. Body dirty reddish-brown. Nematus dorsatus 9
N. caprece (one form), N. acuminatus.

C. As in B, but body provided with distinct tuber-
cles, each ending in a stiff longish hair.

a. Ground colour orange, with black marks, feeding



52 SYNOPSIS OF

in a row in company on the underside of the leaf,
eating only the cuticle. Cladius viminalis.

b. Ground colour green, with yellow and black
markings, feeding on the edge of the leaf. Throwing
off the markings at the last moult ; spinning a single
cocoon. Nematus ribesii, N. consobrinus.

D. Leaf-rolling larvae ; folding down the edge of a
leaf, thus forming a covering under which they live, and
having anal segments ornamented with black markings.
Nematus crassulus, N. bipartitus, Lep., N. nigrolineatus.

E. Gall-inhabiting larvse.

a. Living in galls on leaves,
i. On willow.

1. In bean-shaped galls, ranged in numbers along
each side of the midrib, and projecting from both sides
of the leaf. Nematus gallicola.

In galls longer than broad, placed in pairs one on
each side of the midrib, and projecting more on the
upper than on the lower side. Nematus ischnocerus.

In large oval galls with a considerable internal
cavity. Nematus vesicator.

2. In pea-shaped galls, attached by only a small part
of their surface to the midrib and not at all to the
blades.

Galls smooth, shining, glabrous, generally with
pink or reddish cheeks ; larva changing colour at the
last moult. N. viminalis, N. herbacece.

Galls green, without red, and covered with longish
hair. N. viminalis, N. baccarum.

ii. In pea-shaped galls on Paccinium vitis-idcea. N.
vacciniellus.

b. In galls on twigs of willows or poplars.

i. In large irregular galls on the twigs. Crypto-
campus pentandrce.

ii. In the pith of the young twigs. Cryptocampus
saliceti, C. angustus.

III. With eighteen (rarely twenty) legs. Spinning
a double cocoon, the outer elastic and reticulated.

A. The skin covered with stiff hairs, each issuing



SYNOPSIS OF LARV33. 53

from a tubercle. Yellowish on the back, with the
tubercles black. Hylotoma, rosce.

Not yellow on the back, the tubercles in part yellow.
H. enodis.

B. The skin not covered with stiff hairs.

a. Whitish, with the head and legs black, and the
skin marked with black and luteous spots. H. ber-
beridis.

b. Greenish.

"With white longitudinal lines, and with twenty legs.
H. ustulata.

With a yellow longitudinal line. H. coeruleipennis.

IV. Larvae without any ventral legs, and with long
seven- to eight-jointed antennae.

A. Living socially between leaves spun together with
silken lines.

a. Green or olive green larvae. Living on Pinus



Online LibraryPeter CameronA monograph of the British phytophagous Hymenoptera .. (Volume 1) → online text (page 4 of 31)