difficult groups of the Hymenoptera to define; to a specialist of
course they can be easily separated, but anyone who first takes up the
study of these Micro-hymenoptera (and bear in mind that we are talking
about insects, so small that when a collector breeds them out in jars
he has to liberate them upon a window pane that he may see them against
the light), he will I think endorse Dr. Sharp’s decision. Besides the
peculiarities of the abdomen previously noted, the antennae, sometimes
twice the length of the whole insect, are composed of from 7 to 15
joints, and in the typical groups, though the first joint may be long,
it is not elbowed as in the Chalcids, and is seldom branched. The
wings are delicate, without any nervures, except in a few small groups
where the veins are somewhat like those of small ichneumon wasps. The
hind legs are generally longer than the others, and though some have
the thighs swollen as in the Chalcids, they are as a rule much more
slender, and the abdomen is usually pointed.
They can be bred from galls, particularly those of small Gall-flies
(_Cecidomyia_), the eggs of all kinds of insects, and the larvae of
small beetles, moths, and other wasps.
In Ashmead’s “Monograph of the Proctotrypidae of North America” nearly
600 species are described, and a number have been added since these
were recorded in 1893. The Australian species are probably numerous,
judging from my own observations when studying gall-making insects;
but very few have been described. Westwood described four in his
“Thesaurus Entomologicus, Oxford 1874,” belonging to the BETHYLLIDES,
the peculiarities of which he defines, and figures with coloured
plates. Ashmead describes another (Pro. Linn. Soc. N.S.W. 1900) under
the name of _Ateleopterus longiceps_, obtained by me in a hollow twig
of a wattle tree; a shining black ant-like creature about ⅙ of an inch
in length, rusty red legs, and transparent wings clouded at the base,
probably parasitic on the larva of some wood boring beetle. _Sierola
antipoda_ was bred from the curious bract-like gall of _Cecidomyia
frauenfeldi_ on the twigs of Melaleuca bushes. A second species of this
genus was collected by Webster, and forwarded to Ashmead, who named it
after the sender.
In 1890 Riley described “An Australian Hymenopterous parasite of the
fluted scale” in “Insect Life” which he named _Ophelosia crawfordi_; it
is a tiny reddish brown wasp with a shining black body, and the wings
obscurely barred with smoky brown; it is easily bred from this mealy
bug, which it greatly keeps in check. _Goniozus antipodum_, described
by Westwood from S. Australia, is a little shining black ant-like wasp
which has been lately discovered destroying the grubs of codlin moth
both in S. Australia and N.S. Wales. The larvae feed upon the outside
of the grub, burying their heads in the tissue, and when full grown
spin a loose silken cocoon.
* * * * *
Perkins has recently added a number of new species to this family
belonging to the DRYINIDAE. In his Bulletins Hawaii 1905, Nos. 1 &
10, “Leaf Hoppers and their Natural Enemies,” he describes 45 new
species, chiefly collected by Koebele in Queensland, but some from
the neighbourhood of Sydney. These curious little proctotrypids
are parasitic upon the larvae and pupae of the small homopterous
insects commonly known as Leaf or Frog-hoppers (Families JASSIDAE and
FULGORIDAE). The adult wasp captures the insect, holding it with its
curious clawed feet while it deposits its egg in its body; when full
grown the larva spins a white silken cocoon, from which the active
winged insect emerges in about 18 days.
* * * * *
_Gonotopus australis_ is a tiny wingless ant-like creature about ¹⁄₁₂
of an inch in length, which attacks jassids and fulgorids feeding upon
grass and low herbage. This species comes from Bundaberg Queensland;
but Koebele has bred a second species about ⅛ of an inch in length, of
a general brownish colour, from a Jassid collected near Parramatta. The
curious little sacs or larval bags of these parasites can be readily
noticed projecting from the sides of the thoracic segments. Most of
these insects have well developed wings, but, according to Koebele’s
observations, they stalk their prey when looking for the host for their
egg.
Family 8. Larger Parasitic Wasps.
ICHNEUMONIDAE.
These are commonly known as Ichneumon Flies, and the family is a very
extensive one. They play an important part in the economy of Nature in
destroying thousands of the moth and other larvae that would otherwise
strip our fields and forests of their grass and foliage, and they
are therefore useful allies to the agriculturist; though they also
often destroy other beneficial insects as well as pests, and thus
discount their usefulness. Ichneumon Flies are moderately sized insects
furnished with long slender antennae composed of from 16 to upward of
60 joints, with the basal one often thickened, but never elbowed. The
wings are well developed, with a distinct stigma and numerous nervures
forming regular cells; a few species are wingless in both sexes, but
these exceptional ones have not been recorded from this country.
The legs are long, generally slender, and well adapted for running
about; the abdomen is usually long, rounded or cylindrical, joined
to the thorax on the under side, and more or less stalked, while the
ovipositor of the female is characteristic of the group and adapted or
modified for laying the eggs in or upon the different hosts they prefer
to adopt for their offspring; when they infest wood boring caterpillars
that are somewhat out of reach, the ovipositor is correspondingly long
and the sheath and “tails” produced so as to guide the eggs to their
resting place on the grub, out of the sight of the parent ichneumon.
When the species lays its eggs on the back of leaf-eating insects with
no protective covering, the ovipositor is generally short and stout,
the tip sometimes so stiff and sharp, that several species are credited
with stinging people when handled. The little wasp-grub, hatching from
the egg either deposited on the back or placed beneath the skin, feeds
upon the substance of the body of its victim without touching the vital
organs, so that in most instances where the caterpillar of a moth is
infested, it yet has the power to form its cocoon and pupate before
the wasp-grub has finished growing; the latter thus finishes its final
transformation in the destroyed moth pupa, and cuts its way out through
the side of the cocoon when ready to emerge. Usually, if it is a large
species, the ichneumon deposits only one egg in its victim, but in some
of the smaller ones half a dozen can be bred from a single cocoon. Over
6,000 species of these insects have been described from all parts of
the world, and in many countries, such as this, the native species are
still hardly known, and much confusion exists in their classification
on account of their parasitic habits and the number of different
hosts that the same species may infest; but now that so many economic
entomologists are at work all over the world, it will probably not be
long before they will have many admirers, and a rich field awaits the
entomologist who takes up the study of Australian ichneumons.
Cresson in his “Synopsis of the North American Hymenoptera” lists over
1,100 described species, while in Australia up to the time when Brullé
published his “Histoire Naturelle des Insectes, Hymenopteres,” in 1846,
only one or two had been described, to which he added eighteen species;
Kirby, Smith, Cameron and several foreign entomologists have added a
few more; and in Ashmead’s recent paper ten more Australian species are
described, which makes a very meagre list.
The Spotted Black Ichneumon, _Pimpla intricatoria_, is one of our
largest common species, having a wide distribution over Australia,
and it breeds in a number of different moths. It measures nearly 1
inch in length to the tip of the short ovipositor, and is of a uniform
black colour with red legs and antennae; the thorax and abdomen are
ornamented with pale yellow spots, those on the latter oval, forming a
row on either side.
The Dark-winged Ichneumon, _Rhyssa semipunctata_, is a more slender
species of about the same length; is of a uniform dull red colour
except the basal half of the abdomen, which is black with white
markings on the sides; the wings are clouded with brown, darkest on
the inner portion. These wasps always follow up the cut worms and
caterpillar plagues, and destroy immense numbers in the pupal stage.
The Spotted Ichneumon, _Mesotenus albopictus_, is somewhat smaller,
with slender stalked abdomen and the slender ovipositor turned
downward: the general colour is black, with the antennae marked with
yellow toward the apical portion; the head, thorax and abdomen are
richly marked with light yellow; light brown wings and red legs mottled
with black and yellow. This ichneumon breeds in a great number of
different cocoons, and frequently emerges from the oval cup-like ones
of the “Stinging Caterpillars” (_Doratifera_ and _Limacodes_).
The OPHIONINAE comprises a number of genera, of which the typical
species are reddish brown insects, with clear wings and curiously
curved, laterally flattened bodies, broadest at the extremity. They
are frequently noticed in numbers among the low scrub in the day time,
and in the summer evenings often fly into the house round the lighted
lamp. Six species of the typical Genus _Ophion_ are described from
Australia; but none of the Genus _Anomalon_ have been recorded.
[Illustration:
=Fig. 50.=--_Bassus laetatorius_ (Fabr.). An
Ichneumon wasp that destroys the pupae of Syrphid flies.
(“Agricultural Gazette,” N.S.W.)]
_Bassus laetatorius_ is a well known Ichneumon which has a very wide
range over the globe, and is not a useful species, for it lays its eggs
in the larvae of Syrphid flies, which feed upon different kinds of
plant lice (_Aphis_) and are very useful insects to the gardener. It
measures about ¼ of an inch in length, with the head, thorax, tip and
base of the abdomen black, the rest reddish brown with yellow markings
on the head. The tibiae of the hind legs are very distinctly banded
with white, black, and reddish brown, giving it quite a distinctive
character.
Family 9. Small Ichneumons.
BRACONIDAE.
These are insects with very similar habits but easily separated from
the large ichneumon wasps by the structure of the fore wings, as they
have the outer cross veins wanting, thus showing two long outer cells,
which in the former are divided into two cells. The antennae are always
composed of more than fifteen joints, and the segments of the abdomen
are more soldered together. Many of them, like the _Microgasters_,
are very small, others are as large as many of the smaller true
ichneumons. This country is probably very rich in indigenous species,
while we have a considerable number that have been introduced with
their host insect; but hardly anything has been done in describing our
species. As far back as 1775 Fabricius named 4 species of the typical
Genus _Bracon_, to which only three other species have been added,
though over 500 species are listed in Dalla Torre’s Catalogue in the
cosmopolitan Genus _Bracon_ from other parts of the globe.
The typical Braconid is usually very small; many of them are no larger
than some of the Chalcids. Wherever the cabbage aphis or other plant
infesting insects such as caterpillars are to be found, these little
wasps can be observed hovering round, waiting for an opportunity to
deposit their eggs. They differ from the large ichneumons, in that
while the latter only deposit a single, or at most a dozen eggs upon
a victim, these often place hundreds in a large caterpillar, which,
emerging when full grown, form little white oval silken cocoons on the
top of the remains of their hosts, that are sometimes surrounded with
a mass of white fibre exactly like cotton wool. After a plague of cut
worms has passed over a paddock it is quite common to find clusters
of these little cocoons attached to the grass stalks; these have been
often sent to me from the country with the information that they were
the eggs of the plague caterpillars or cut worms.
[Illustration:
=Fig. 51.=--_Ephedrus persicae_ (Froggatt). A
Braconid wasp that lays its eggs on the bodies of aphids.
(“Agricultural Gazette,” N.S.W.)]
_Bracon limbatus_, one of our larger typical species, is found in
Tasmania, and has a wide range over Australia. It measures about ½ an
inch from the front of the head to the tip of the abdomen, and is of
a general black colour on the upper surface, with dusky almost black
wings, and a red head. The under-surface is marked with brown, with
the thorax, thighs, and tibiae of the front and middle legs black;
the three slender curled hair-like tails forming the ovipositor being
longer than the whole insect. Eight other species of _Bracon_ are
described, several of which are also recorded from New Guinea and
New Zealand. Among the introduced species is _Lepolexis rapae_ of
Curtis, which is parasitic upon the cabbage aphis in Europe; it can be
collected in gardens about Sydney. Aphids containing these parasites
are always swollen, round, and apparently dead skins through which each
braconid eats its way.
Five species of the Genus _Agathes_ are described; they are remarkable
for their showy particoloured wings, and large size in comparison
with other members of this family. Ashmead has described a tiny black
species marked with yellow bred by me from the larva of a Noctuid Moth,
an undetermined species of _Agrotis_, under the name of _Apanteles
antipoda_; and a second larger one as _Apanteles australasiae_. In
his Genus _Microbracon_ he has described a dainty little black and
yellow creature that infests the larvae of our scale-eating moth
(_Thalpochares coccophaga_) under the name of _Microbracon thalpocaris_.
Family 10. Ruby Wasps.
CHRYSIDIDAE.
The popular and scientific names of these insects refer to the
brilliant metallic blue, green, golden or copper coloured tints
of their armour-plated bodies, which are also covered with coarse
punctures, finest upon the abdomen. They are stout thickset wasps with
short curled antennae and large eyes; the thorax is broad and closely
attached to the abdomen, the latter composed of from three to five
segments, the first generally much shorter than the second, with the
last toothed along the hind margin, and characteristic of the different
species; the under-surface of these plates is concave, with the tip of
the abdomen produced into a tubular process, so that when alarmed the
wasp can curl her body round into a ball, protected on all sides by
the armour-like integument; and as she lays her eggs in the nests of
other wasps and bees, and is sometimes caught in the act, this habit
is probably a wise provision of Nature which enables her to resist the
sting of the lawful nest maker.
Some of the earlier observers called them “Cuckoo Wasps,” under the
impression that their larvae, when hatched out in the nests of hunting
wasps or bees that filled the cells with insects or bee bread, fed
upon the stored food supplies, but later researches show that, though
the egg of both the lawful occupant and the intruder may be deposited
in the cell, the latter does not hatch until the former has devoured
all the food placed there by his mother and is ready to pupate; then
the ruby wasp baby comes out, attaches itself to the full fed larva
beside it, and sucks him dry, pupating in his skin.
Most of our species that I have bred out are parasitic in the clay
nests of the smaller Mason Wasps, _Odynerus_ and _Alastor_, though in
Europe many species live in the nests of bees. The perfect insects are
generally found crawling over or flying round old fences or stumps and
dead trees in the hottest part of the day. Our species were described
by F. Smith in 1874 in his revision of the family, in the Transactions
of the Entomological Society of London; a few others have since been
added to the list by Mocsáry, who monographed the Chrysididae in 1889;
and Gribodo in the Annals of the Mus. Geneva, 1879.
No member of the typical Genus _Cleptes_ common in Europe and America
is recorded from Australia; but two well defined species of the
beautiful ruby wasps of the Genus _Stilbum_ that has a world wide range
are described, _Stilbum splendidum_ confined to Australia and New
Caledonia, and _Stilbum amethystinium_, found also in Asia, Africa and
America. The great Genus _Chrysis_, which contains over 600 described
species, is represented here by about 27 species.
Family 11. Hatchet-bodied Wasps.
EVANIIDAE.
Under the recent classification of this family it now comprises three
very well defined genera, which have moderately thick antennae, not
elbowed, consisting of thirteen or fourteen joints; the nervures of
the wings not so well defined as those of the Ichneumons; and the
stalked abdomen attached to the upper part of the metathorax. They are
well represented in this country, and have been chiefly described by
Westwood and Schletterer.
[Illustration: Plate XIII.--HYMENOPTERA.
Family MEGALYRIDAE.
1. _Megalyra fasciipennis_ (Westwood). ♀.
Family ICHNEUMONIDAE.
2. _Pimpla intricatoria_ (Fabr.). ♀.
Family EVANIIDAE.
3. _Gasteruption sp._
Family MUTILLIDAE.
4. _Mutilla formicaria_ (Westwood). ♀.
Family CHRYSIDIDAE.
5. _Stilbum splendidum_ (Fabr.).
Family THYNNIDAE.
6. _Diamma bicolor_ (Westwood).
10. _Thynnus variabilis_ (Kirby). ♀.
11. _Thynnus variabilis_ (Kirby). ♂.
Family SCOLIIDAE.
7. _Trielus zonata_ (Smith). ♀.
8. _Discolia verticalis_ (Fabr.). ♂.
9. _Discolia soror_ (Smith). ♀.
Family SPHEGIDAE.
12. _Bembex tridentifera_ (Smith).
(Original photo. Burton.)]
[Illustration: _Plate XIII.--HYMENOPTERA._]
The members of the typical Genus _Evania_ are generally shining black
insects, sometimes variegated with dull red markings; the head and
thorax are short and broad; the abdomen has the first segment produced
into a slender stalk, and the remaining ones forming a vertically
compressed hatchet-like body. They are parasitic upon the egg cases of
cockroaches; some with a very wide range have been introduced in
all probability with their cosmopolitan hosts, while they are often
found in the house flying on the window panes, evidently introduced in
the same manner. In the bush the perfect insects are commonly found on
flowering shrubs in the summer time. About 20 species are described
from Australia and Tasmania. _Evania princeps_ is of a uniform black
colour with dusky wings, and is recorded from most parts of Australia,
Woodlark Island and New Guinea. It is one of our largest species,
measuring ½ an inch in length, broad in proportion, and furnished with
very long spined legs.
The Genus _Gasteruption_, which takes the place of the Genus _Foenus_
in the earlier catalogues, contains 36 described species from
Australia; as they are rare insects, there are probably many more to be
discovered. Nothing is known about their habits for certain, but they
are supposed to be parasitic upon the larvae of wood boring insects;
I have generally found them flying round the trunk of a dead or burnt
tree. They differ from the former genus in having the head almost
globular, with antennae standing out straight in front, and large oval
eyes on the sides; the thorax is more elongate, rounded in front, so
that the insect appears to have a slight neck. The abdomen springs from
a rounded node on the thorax, with the basal segments slender, swelling
out gradually, and broadest at the tip; the females bear a very long
hair-like ovipositor. The legs are slender, the hind pair longest,
with both the thighs and apical half of the tibiae thickened in a very
distinctive manner. Ten species are described from Sydney; and one,
_Gasteruption pedunculatum_, is also common to New Zealand.
The Genus _Aulacus_ contains ten described species of smaller insects.
_Aulacus apicalis_ is parasitic upon the larvae of a longicorn beetle
(_Piesarthrius marginellus_). I have found as many as fifty, each
enclosed in a thin parchment cocoon, all matted together in a single
cavity. This little wasp has a long extended ovipositor, and measures
about ½ an inch in length; the head and greater portion of the abdomen
is black, the rest reddish brown, with a blotch of yellow on the upper
surface of the base of the abdomen; the hyaline wings are tipped with
black.
Family 12. Long-tailed Wasps.
MEGALYRIDAE.
These remarkable parasitic wasps, peculiar to Australia, are comprised
in a single genus containing 16 species, none of which are very common.
They are all shining black insects; the head short, broad and almost
rounded, the thorax broad and stout, both very rugose and clothed
with fine silvery hairs on the sides; the eyes large, circular, and
very prominent; ocelli small; the antennae composed of irregular wiry
joints; the wings semitransparent, generally banded with black, and
the transverse nervures wanting in the apical half; legs long, with
the thighs thickened. The abdomen is closely attached to the thorax,
cylindrical, tapering to the extremity, and in the females furnished
with an ovipositor often more than three times the whole length of the
insect, looking exactly like three black horse-hairs. These elongated
ovipositors are used for depositing their eggs in the wood-boring
larvae of longicorn beetles belonging to the Genus _Phoracantha_,
and probably others of like habits, which feed under the bark in the
sap wood of different eucalypts. The perfect insects are generally
found about flowers on low shrubs in summer.
_Megalyra shuchardi_ is of the usual black colour with silvery
pubescence; the wings are pitch black and opaque: the whole insect
measures slightly under 1 inch in length, with the ovipositor over
three inches. It is found in Victoria and New South Wales, and
also recorded from Melville Island on the North Coast. _Megalyra
fasciipennis_ was described by Westwood when he founded the genus,
in the Transactions of the Entomological Society 1841; and it is again
figured in Griffith’s Animal Kingdom, Insects, Vol. II. It is much
smaller than the previous one, of similar form, the legs and ovipositor
reddish brown, the wings hyaline, barred across the centre and clouded
at the extremities with blackish brown. The male is much smaller than
the female, with similar wings, but the body is more slender and comes
to a point at the tip, furnished with a curious bifid anal appendage.
This is the species we have found breeding from the longicorn larvae.
Six other species have been described, some by Schletterer (Berliner
Entom. Zeitschrift 1889); one, _Megalyra melanoptera_, closely allied
to Westwood’s dark winged species. In 1902 Szepligeti (Termes Z.
Fuzetek, xxv.) monographed the family and added one more; and Bradley
last year, describing the last new form (Trans. Ent. Society of London
1905) appends a translation of the former’s tabulation of all the
known species, seven in number. I have (Pro. Linn. Soc. N.S.W. 1906)
since added 8 new species to the list.
Family 13. Ants.
FORMICIDAE.
The ants are among the first insects that attract one’s notice in a
new country; civilization seems to agree with many species which form
their nests in the lawns or gardens, and even take up their quarters
in the house. Within the last decade a small introduced species has
appeared in the heart of London, and the small red ant, _Monomorium
pharaonis_, is a world wide pest in houses from Europe to Australia.
Ants live in communities forming nests in the ground, under logs or
stones, or in dead trees, and sometimes among the foliage of plants.
These communities consist of winged males and females, and wingless
aborted females known as workers, the bulk of the family consisting of
the latter; in some groups there are several varieties of workers, that
are often called soldiers on account of their great size and swollen
heads. In those species that are furnished with a sting both the
workers and winged females should be handled with care.