Australian insects

House flies are well known to everyone; but as a number of other insects belonging to different orders are often called flies, such as “saw-flies,” which are Hymenoptera, and “lace-winged flies” and “May-flies,” which are Neuroptera, it is advisable to define them. Some of the Diptera might be mistaken by a casual observer for Hymenoptera which the members of several families often mimic in form and colouration, but they can be readily separated by the absence of a second pair of wings, which are represented by two little clubbed processes, known as balancers, poisers, or halteres. The mouth parts are very variable in structure in the different groups, but always adapted for piercing or sucking; the eyes are large, often occupying the greater part of the head and consisting of an immense number of fine facets; the small ocelli are three in number; and the antennae, except among midges, are short, composed of few joints, and often terminate in a bristle.

The thorax is not so distinctly divided into the three segments as in some other insects, nor the parts so well defined as in the hymenoptera; the wings, transparent or parchment-like, are seldom coloured; the legs, usually not thickened, are furnished with five tarsi, and well developed claws, with a small pad under each, known as the pulvillus. The abdomen is composed of a variable number of segments ranging from four to nine, but in the former case though not visible the terminal ones are probably absorbed into the anal tube at the extremity. Most diptera are brown, black, or grey, though metallic tints predominate in some families; and are clothed with short scattered hairs or bristles.

The typical fly larva is an elongated legless maggot with the head portion slender, enclosing a pair of black retractile hooked jaws, with tracheae opening behind and running through to the broadened anal segment where they form small rosette-like processes round the external aperture. The eggs are laid in all kinds of decaying vegetable or animal matter, with the exception of the few that produce galls, or otherwise damage plant tissue; when full grown they change into a hard shell-like chrysalis, the tip of which is pushed off by the perfect fly when ready to emerge.

Though this country is very rich in Diptera and many cosmopolitan species have been introduced such as the house flies, they have been much neglected by Australian collectors and entomologists. The Diptera are divided into two large sections, which are further subdivided into four main groups, to which a fifth has been lately added for the reception of the fleas, which however are often placed by specialists in a class by themselves (Siphonaptera). The older writers subdivided them into about 70 families but latterly these have been reduced, and most of our species will come under about 30 families, of which I can only note our most striking representatives.

In 1830 the French naturalist Robineau Desvoidy published his “Essai sur les Myodaires,” in which some of our species were described. Between the years 1834 and 1835 Macquart brought out his “Histoire naturelle des Insectes Diptères” (forming part of the great French work Suites à Buffon), followed (1838–42) by his “Diptères exotiques, nouveaux ou peu connus” comprising two volumes and many plates, with 5 supplements (1846–55). Walker between 1848 and 1855 compiled a “Catalogue of the Diptera of the British Museum” consisting of 7 volumes; and others are described in his “Diptera Saundersiana” 1856.

In 1864 Dr. Schiner estimated that the number of described Australian Diptera was 1056, including those which he described (Diptera des Novara), collected by Frauenfeld in the neighbourhood of Sydney during the visit of the Austrian Frigate. In a long series of papers reaching from 1859 till just before his death in 1892 Bigot described a great many species (among them some from Australia) chiefly in the Annales de la Societé Entomologique de France.

The only systematic Australian work is Skuse’s “Monograph of the Australian Diptera” (Pro. Linn. Soc. N.S.W. 1888–90), which however was never completed, dealing only with the Nematocera comprising the Culicidae, Tipulidae, Cecidomyidae and some of the smaller families. There is no complete catalogue of Australian Diptera, but I have been greatly assisted in my work on this family through the identification of my specimens by Mr. Coquillett of Washington.

Family 1. Gall-Gnats.
CECIDOMYIDAE.

This is an extensive family of small delicate midges with long slender antennae composed of many bead-like segments beautifully feathered with whorls of hairs. The abdomen is stout at the base, short and tapering to the tip; the legs are long and slender without spurs; the wings are clothed with fine hairs that easily rub off, and furnished with very few longitudinal veins, and in some genera only one cross nervure.

They are known as “Gall-gnats,” or “Gall-flies,” and though the habits of the larvae are very diverse, some living under bark, others in animal matter, and a few predaceous or even cannibalistic in their habits, the majority of them are found in plant tissue and produce malformations or regular well defined galls, often of very remarkable structure, upon the foliage or twigs of their food plant.

The egg is deposited in or under the bark, epidermis of the leaf, or frequently in the flower buds of plants, the irritation caused by the active larvae producing the aborted tissue. These larvae are very easily recognised if examined with a lens after they have been extracted from the gall, as they are furnished with a “breast bone,” an anchor shaped process that stands out very distinctly in the centre of the ventral surface and is unknown in the larvae of any other gall-producing insect.

Through the discovery of Wagner, a Russian entomologist, that the larva of a Cecidomyia produced young; also through the curious exudations of the larvae and pupae of others which are sometimes called “flax seed” from their shape; and the very destructive habits of several species which damage the wheat, like the Hessian Fly in America, this family has received a great deal of attention. Over 1,000 species have been described from all parts of the world, and Australia is particularly rich in these insects. Skuse (Pro. Linn. Soc. N.S.W. 1888 and 1890) has described over 100 species and figured some of the most peculiar galls.

Cecidomyia frauenfeldi was named by Dr. Schiner after the naturalist who collected the galls on Leptospermum in the vicinity of Manly, N.S. Wales. These galls are produced upon a leaf-bud and consist of a number of rounded leaf-like bracts, not unlike the petals of a rose bud; folding over each other, brown in colour, soft and loose, and about the shape and size of a small marble. The enfolded larva will be found in the base at the centre, and the gnats can be easily bred out in a glass jar. The Acacia Gall-gnat, C. acaciae-longifoliae, infests the flowers of this wattle, depositing its eggs in such numbers that every tiny seed-pod is produced into a contorted mass of finger-like tubes, together forming a rounded base attached by a stalk, and each tube containing a larva. This is one of our commonest species and the galls can often be collected in numbers in the neighbourhood of Sydney.

Diplosis frenelae produces very remarkable little light brown spherical structures upon the tips of the foliage of the desert cypress, about the size of small peas; these when mature split into four shell-like sections, quite unlike the usual gall. They are very abundant in the early summer upon cypresses in Wagga and the western pine scrubs of N.S. Wales. Diplosis paralis forms curious little blisters upon the young foliage of Eucalyptus corymbosa, dotting the leaves all over with reddish spots with a keyhole-like mark on the apex. A third species, D. eucalypti, aborts the young twigs of Eucalypts into gouty swellings in which a number of larvae feed and pupate.

There are certain red rounded shot-like galls of the Eucalyptus, generally several in number on the midrib of the leaf, which, on account of the pupal skins always remaining in the holes in the sides of the galls through which the flies have escaped, can be easily distinguished from many very similar ones that are the work of micro-hymenoptera. These are formed by a large stout gnat named Hormomyia omalanthi by Skuse, who first obtained specimens from galls on the under side of the leaves of Omalanthus populifolius.

Lasioptera miscella aborts the leaf stalks of Eucalyptus haemastoma, one of our white stemmed gums growing about Botany, N.S.W., with its irregular swellings.

I have also bred several undetermined species from galls on the twigs of the Weeping Myall, Acacia pendula, and other wattles in the western scrubs. There is a rich field awaiting the naturalist who takes up the study of the life-history of our Gall-gnats.

Though the Hessian Fly, Cecidomyia destructor, is not known in Australia it has been introduced into New Zealand, and in the United States of America is one of the most serious pests that the wheat farmers have to fight. This gnat deposits her eggs under the sheath of the growing wheat stalks; the larva sucks up the sap, so that the ear is impoverished and no grain forms in the head; and when they are numerous the greater part of the crop is destroyed.

Family 2. Shade Midges.
MYCETOPHILIDAE.

These small flies, popularly known as “Midges,” are placed by Skuse in four well defined families, which I place under the one heading as their habits are very similar.

The Sciaridae are the typical “Shade midges” infesting forest country; their larvae live under dead bark or decomposing leaves and are slender, cylindrical, semi-translucent maggots, white or pale yellow in colour, with the body composed of 13 segments including the head. The perfect insects have moderately long, curved, many jointed antennae; two ocelli; long slender legs; and the wings often clouded. Skuse has described 42 species in this group, all of which with one exception he placed in the typical Genus Sciara; these have the wings longer than the abdomen, the surface of them microscopically pubescent, and the wing-lobes more or less developed.

The Mycetophilidae are popularly known as “Fungus-midges” from the fact that the larvae, which are slender white maggots attenuated at both extremities, and with horny heads, are often found feeding upon the juices of fungi; some spin silken webs under which they live, and a few are said to be luminous. They are small flies with beautifully marked wings in many species, and have slender antennae; 3 ocelli; and a short proboscis; the rather long legs have the coxae elongated and are furnished with spurs upon the tibiae; the wings, without a discoidal cell, have more veins than those of the Gall-gnats. Walker described 4 species (Insecta Saundersiana 1856); to which Skuse added 31 new species. Lyomya setiosicaudata was described by Skuse from the neighbourhood of Sydney in the Genus Acrodicrania, but it has an extended range: I have taken it with a sweeping net about Inverell N.S. Wales. It measures about ⅙ of an inch in length; has a shining head and thorax; abdomen black, and variegated black and yellow legs.

The Simulidae contains a number of small Diptera abundant in Europe and America, where they are known as “Sand-flies,” “Black-flies,” or “Buffalo-gnats”; they swarm in the marshy lands of the Mississippi where Howard says, “They rival the mosquito in their blood-thirsty tendencies, and not only do they attack human-beings, but poultry and domestic animals are frequently killed by them.” We are fortunate in having very few of these pests; only one species was discovered by Skuse, who named it Simulium furiosum, and says it is a rare fly only found in the Gosford district N.S. Wales. These flies must not be confounded with the midges known in Australia as “Sand-flies,” which are very different insects belonging to the Genus Ceratopogon, of the Family Chironomidae.

The Bibionidae are medium sized flies with thickset bodies somewhat hairy; smoky wings; robust legs; short antennae; and three ocelli. The females deposit their eggs in dung or vegetable matter, and the maggots have rows of transverse bristles on the segments; and traces of eyes can be found in the head segment. The perfect flies are sluggish in their movements and are commonly found upon flowers. Twelve species have been described from Australia, of which Bibio imitator is our commonest species; it is very abundant in the early summer upon the flower heads of Astrotricha floccosa, which grows in most of the valleys round Sydney; it has a wide range from Tasmania northwards in similar forest country. The male is under ½ an inch in length and is of a uniform black tint, with the thorax dull red; while the larger female is of a uniform reddish brown, and both sexes have the typical dark clouded wings.

The South American Genus Plecia is represented by four species, two of which I collected in North Queensland. The North American Genus Scatopse, the larvae of which breed in all kinds of decaying matter and in sewers, is represented by two species, of which Scatopse fenestralis is so common about Sydney that Skuse says: “In the spring months it is scarcely possible to find a window without one or two specimens, while I have frequently seen hundreds swarming on the inside of shop windows in the city.”

Family 3. Mosquitoes.
CULICIDAE.

No insect pests are better known or more world wide in their distribution than mosquitoes. As might be expected, they are abundant in tropical countries, yet one would hardly expect them to be much of an annoyance in the temperate regions. Yet in Lapland, and even farther north, they worry the inhabitants and the reindeer all through their brief summer.

Plate XXVII.—DIPTERA.

Family Culciidae.

They are insects with long slender legs; delicate narrow wings folded down over an elongate body; the head is provided with a proboscis projecting below. The proboscis is adapted for sucking blood, though many of the bush species seldom or never taste blood and obtain their nutriment from the sap or moisture upon plants. The male mosquito is a more delicate creature than the female, furnished with plumose antennae; he does not bite, but hides away in dark sheltered corners taking no food in his short life of four or five days, but has a low droning hum, noticeable when a number are disturbed. The larger females on the other hand swarm into the house, and bite whenever they get the chance. She lays her eggs in little boat shaped masses of elongate eggs, which within 24 hours give birth to larvae that are often called water-fleas or “wrigglers.” Thread-like in form at first, the “wriggler” has a rounded ciliate head, and the tip of the body is provided with a pair of tubular breathing appendages. They move about with a series of jerks, always coming to the surface head downward; they increase in size rapidly and in seven or eight days are full grown, when they change into pupae, the creatures becoming quite different; the head and thorax are drawn up into a rounded mass with two trumpet shaped horns, which are its new breathing tubes, rising upon the sides. The abdominal segments are short and turn downward; and though it does wriggle slightly, it usually rests in an upright position floating close to the surface; it remains in this state for two or three days, when the pupal skin splits along the top of the head, and the perfect insect emerges, using the floating skin as a raft from which to rise into the air and fly away.

Only 9 species of mosquitoes had been described from Australia when Skuse commenced his work on these insects in the Macleay Museum Collections (Pro. Linn. Soc. N.S.W. 1889), where he listed all the known species and added 19 new ones. Since then Theobald, in his “Monograph of the Culicidae of the World” 1900–1903, with a great deal more material to study, revised the genera, made several of Skuse’s species synonymous, and described others, bringing our list to about 34 species.

The typical Genus Culex contains 21 species scattered all over Australia; several are cosmopolitan and have been introduced from abroad. Our common house mosquito, that appears in the early summer, is Culex albo-annulatus, a moderate sized species with the reddish thorax densely clothed with brownish golden scales, traversed by five very fine lines; it has regularly white banded legs. It was described by Macquart in 1732, and ranges from Southern Queensland to Sydney, Mittagong, and the Blue Mountains N.S.W. Culex fatigans is widely distributed over Australia: C. macleayi and C. skusei according to Theobald are only sub-species or varieties; it is one of the cosmopolitan mosquitoes also found in America, Africa and Asia, and was probably introduced into this country in the water tanks of the old sailing vessels many years ago. After New Year a smaller, darker mosquito is the most annoying about Sydney; this has been described by Theobald under the name of Culex marinus; its larvae were discovered by Dr. Bancroft, Queensland, breeding in salt water. It also flourishes freely in any stagnant water left in tanks, buckets, or water-holes, and has a wide range down our eastern coast.

Four species of the Genus Anopheles are found in Australia; these insects have long palpi with clubbed or spatulate tips, and dark spotted wings. Anopheles annulipes, described by Walker, said to be identical with Skuse’s A. musivus, is found about Sydney and Newcastle N.S.W. ranging northward; the members of this genus are well known as the mosquitoes that transmit the germs of malarial fever, and have a wide range over the world. The important results that have come from the study of the relation of tropical fevers to mosquito bites, have led to the collection and description of these insects from all quarters of the globe. Mucidus alternans, one of our largest species, is thickly clothed with grey and light brown scales and hairs which give it a striking appearance. It is a day flying species famous for its biting powers; it has a wide range; in the Maitland district N.S.W. about the Hexham swamps it is locally known as the “Hexham Grey”; in Queensland it is sometimes called the “Scotch Grey.” I have also taken it at Bourke on the Darling River N.S.W. Skuse described this species as Culex hispidosus, but Westwood’s name, C. alternans, has a prior claim.

Stegomyia notoscriptus is one of the small dark mosquitoes that bite so sharply just at dusk in our gardens around Sydney in midsummer, and has a wide range from Adelaide S.A. to Queensland. It belongs to the same genus as the dreaded Cuban Yellow-fever Mosquito, Stegomyia fasciata, which has been introduced into Hawaii. Theobald has in the last volume of his Monograph formed a new Genus Skusea for the reception of two Queensland species and a third from Africa.

Family 4. Sand-flies.
CHIRONOMIDAE.

This group comprises a number of small flies which have the head furnished with a fleshy proboscis; the slender antennae adorned with fine hairs, thickest upon the male; and the ocelli wanting. Their wings are usually narrow; and many of the large species have the general appearance of mosquitoes.

The members of this family are very extensive and world-wide in their range; the larvae of the typical Genus Chironomus live chiefly in stagnant water. They sometimes swarm in such numbers in the North American lakes that they form the chief food of the fresh-water fish. In England on account of their colour they are known as “blood-worms.” Some species live in salt water, and others breed in excrement and dung. The perfect insects are easily collected with a sweeping net in the vicinity of swamps and watercourses.

Skuse has described 64 species from Australia (Pro. Linn. Soc. N.S.W. 1889), previous to which only 8 species, described by Messrs. Walker and Macquart, had been recorded. The family is divided into a number of genera, of which Chironomus includes 21 species of the more typical slender-bodied midges, and the Genus Ceratopogon 17 species of our vicious “Sand-flies.” These pests are also found in Great Britain and in North America, ranging as far south as Chili.

Ceratopogon molestes, described by Skuse, is our common “Sand-fly,” though there are others probably quite as annoying if not so abundant. It is a tiny little dark coloured midge, so quiet and small that it is usually felt before it is seen. There is another very large grey “Sand-fly” I have met with in the interior of N.S. Wales on the Darling River that frequents grassy watercourses and flies straight at the hands or face like a wasp.

It has been reported from Central Queensland that after the great flood and abundant growth of grass (1905) the sand-flies increased in such numbers, that they caused the blindness and death of a great number of marsupials, through biting them in the eyes.

Family 5. Crane-flies.
TIPULIDAE.

The Crane-flies or Daddy-longlegs are a large family with long slender legs, from which they take their popular names, and might be described as exaggerated mosquitoes that do not bite. They have the usual small head and long thread-like antennae (in some groups the latter are clothed with long hairs, in others short and feathered); in most species the ocelli are wanting. The thorax has a V-shaped transverse suture, and the well developed wings have a complete venation. They are to be found in all situations among low scrub, but prefer the shelter of cliffs, or tree trunks in damp gullies, often resting in considerable numbers in retired spots during the day, where they can easily be captured. They require to be killed and mounted in the place of capture to secure good specimens, as their legs drop off very readily, and on this account are not a popular group with the ordinary collector. The larvae live in the ground or among decaying vegetable matter.

They are divided into two large groups, characterised by the possession of long or short palpi, the Tipulidae brevipalpi and Tipulidae longipalpi; about 20 species had been recorded from Australia when Skuse’s Monograph, “Diptera of Australia Pt. VII.” (Pro. Linn. Soc. N.S.W. 1889) appeared; in this he added over 80 new species.

The Painted Crane-fly, Gynoplistia bella, described by Walker in 1835, is one of our commonest species, frequenting flowers and low scrub in the early summer months. It is a very distinctly marked black and orange yellow fly, the wings thickly barred and mottled with the former colour; and is one of the short-legged species. It has a wide range from Western Australia and Tasmania to N.S. Wales; the genus is represented by 17 described species in Australia.

The Long-horned Crane-fly, Macromastix costalis, has a wide range from Tasmania to Queensland. In the neighbourhood of Sydney they are commonly found resting among the low scrub. It has a uniform dull brown tint with clear transparent wings, striped along the front margin with dull brown, and can be easily recognised from its large size, with the long slender antennae three times the length of the wings in the male, and its curious darting flight when disturbed. It was described by Swederus as Tipula costalis in 1787, and has been renamed half a dozen times since. Clytocosmus helmsi was described by Skuse from specimens obtained at Mt. Kosciusko; it is a large handsome fly with the stout thickened abdomen black, and bordered or mottled along the segments with white; the wings are semitransparent shaded with yellow; the head and thorax are reddish yellow.

The Genus Semnotes contains two very large and handsome crane-flies, both of which were originally described by Westwood. They are giants of the family, with a large thorax, and swollen abdomen narrowed slightly into a waist, coming out broad and rounded to the tip; the general colour is bright yellow mottled with black, with semitransparent wings. Semnotes ducalis has dark markings on the wing, and is the rarer species. It is recorded by Westwood from North Australia, and by Skuse from Manly, N.S.W. S. imperatoria is found in Victoria, about Sydney and the Blue Mountains N.S.W.; it is slightly larger than the former, and can be easily distinguished by the very long tarsi, the plain wings, and the different markings on the body.

Family 6. Soldier Flies.
STRATIOMYIDAE.

These are flat-bodied flies with narrow strongly veined wings; 3-jointed antennae; and the pronotum furnished with slender spines. Comstock has called them “Soldier Flies” on account of the bright coloured stripes with which many species are marked. The larvae of most of these flies live in decaying vegetable matter, but some are known to be carnivorous in their habits.

Neoexaireta spinigera is one of our commonest species, often to be found in the early summer months resting on the window pane with its broad hind legs flattened out; it is very easily captured. It is a slender shining black fly about 1 inch in length, with banded legs; the sides of the body fringed with white hairs, and the apical half of the wings clouded with black enclosing a small white blotch; the pronotum is furnished with four slender spines standing out from the hind margin. The larvae are usually found under damp rotting bark or decaying vegetable matter, and are elongate flattened brownish and distinctly segmented creatures, with narrow horny heads standing out in front like a stalk; they are sluggish creatures with very little movement. I figured and described a species (doubtfully) under the name of Ephippium albitarsis in my “Entomology of the Grass-trees” (Pro. Linn. Soc. N.S.W. 1896) with somewhat similar larvae breeding in the decaying stems of these trees. The little black fly measures about ⅓ of an inch in length; it has white tarsi and dusky wings; the pronotum has the usual short spine on either side; and the legs are stout. Odontomyia stylata is an elongate, broad, flattened, bronzy green fly with the outer edges of the abdomen light green; and the long pointed wings are folded down over the back; the head is very broad; the rounded thorax is long, furnished with two small spines behind the pronotum, and the abdomen is broadly rounded at the tip. It is a common rather large fly about ½ an inch in length, usually found resting on foliage in damp places. It has a wide range over Australia. In other parts of the world these flies are numerous, and about 1,000 species of the family have been described.

Family 7. March Flies.
TABANIDAE.

These flies are large or moderate sized insects, with broad heads furnished with a fleshy proboscis well adapted for biting; the 4-jointed antennae stand out in front of the head and do not terminate in a bristle; in the male the large eyes meet in front, but in the female are separated; the wings are large, often long, and well adapted for flight; the legs moderately stout; and the abdomen long, broad, and somewhat flattened.

They are common in the early summer months in open forest country, and are popularly known in Australia as “March Flies”; in England and America they usually go under the name of “Horse or Gad Flies,” and are a great pest to both man and horse; they are so persistent in their endeavours to bite and suck up blood that they are very easily captured with the hand.

The larvae of Tabanidae live in damp earth, or are found in water; they are carnivorous, feeding upon larvae and pond snails. The flies deposit their eggs in bunches on herbage or low shrubs. These flies are very interesting from an economic point of view, for they are said to be sometimes responsible for outbreaks of anthrax by introducing the bacillus when biting. Some years ago an outbreak of malignant pustules on cattle in New Caledonia was said to have been traced to an undetermined species of Pangonia (Megnin and Germain, Bulletin Soc. Ent. France Vol. viii. ser. 5).

The Genus Pangonia is well represented in this country by many large handsome flies that differ from the typical Tabanus in having ocelli, and the third joint of the antennae elongate instead of compressed. Pangonia guttata was figured by Donovan in his “Insects of New Holland”; it measures over 1 inch in length, and is broad in proportion; its general colour is black, clothed with little tufts of white downy hairs fringing the thorax in front of the wings, and forming a band round the outer edge, with similar spots down the centre of the abdominal segments; the under-surface is variegated with longer white and black hairs, and the wings are clouded with black. This large handsome fly is common in the coastal forests, usually found resting on tree trunks in the heat of the day. P. rufovittata is a smaller more showy insect of a dull yellow colour. The eyes, parallel markings on the thorax, and broad transverse bands on the abdomen of black, the alternate abdominal bands of beautiful golden hairs, together with the yellow clouded wings, give it a very striking appearance; it also has a wide range over Australia, and is occasionally taken in the neighbourhood of Sydney. P. auriflus, about ½ an inch in length, also black, has the face, front of thorax, under-surface and outer margins of the abdomen clothed with silvery hairs, while the hind margin of the thorax, a blotch in the centre, and the tip of the abdomen are richly coloured with bright yellow hairs. P. concolor, a much larger fly, is of a uniform reddish brown colour, with black eyes, and mottled wings; P. violacea is a small bright metallic violet tinted insect not unlike a blue bottle fly, but is easily distinguished when the antennae are examined.

The Genus Tabanus contains many of the typical “March Flies”: Tabanus brevidentatus measures ½ an inch in length; is of a uniform grey ash colour, with the hind edges of the abdominal segments barred with light brown. T. edentulus is a slightly larger, darker coloured fly with greyer bands on the body; it is common on the slopes of Mt. Kosciusko. T. abstersus is still larger and darker, but with the same general colour; the head and under-surface are clothed with white hairs; the wings clouded; the base and sides of the abdomen reddish brown with the dorsal surface barred with fine white hairs. T. sanguinarius, one of the largest species, is of a uniform reddish brown, with black eyes; the thorax tinted with yellow; and the wings clouded. It has a wide range over Queensland and N.S. Wales. Silvius angusta is like a very small specimen of Tabanus brevidentatus.

The members of the small Family Leptidae are distinguished from the preceding one, in having the third joint of the antennae simple and furnished with a bristle, and the tibiae spined. The curious looking larvae have the abdomen divided into two points at the tip; they live in pits like the ant-lions. Leptis aequalis is a greyish looking species about the size of a house fly, with the head composed of two large globular eyes touching in the centre; the legs are long; the wings smoky; the elongated abdomen rounded at the tip, and barred with black; the whole insect clothed with scattered hairs standing up thickly on the dorsal surface. These flies are very common flying over aphis infested wheat fields; my specimens come from Molong, N.S. Wales.

Family 8. Bee-flies.
BOMBYLIDAE.

These are popularly known as bee-flies, on account of their remarkable powers of flight, and hairy appearance. They are all more or less clothed with delicate downy hairs, furnished with 3 jointed antennae, and slender legs terminating in fine claws.

They frequent flowers, hovering over them like bees; and many species have the wings richly marked with black. The life history of our species is but little known, but I have bred several out of the clay nests of wasps, and two out of lepidopterous pupae (Agrotis sp.). A European species is said to drop her eggs upon the clay nests of wasps; the newly hatched larva is furnished with a boring apparatus in front of its head by means of which it works its way through into the chamber; there it undergoes another stage of development and emerges from it with a simple sucking mouth to eat up the wasp larva. The larva of those attacking the “cut-worms,” Agrotis, devours the whole of the moth grub and pupates inside the chrysalid skin. The pupa is a very curious looking creature enclosed in a dark brown shining skin about ¾ of an inch long, with projecting spines on the head and extremity. The body is cylindrical with the first 7 segments furnished with a band of rasp-like spines or ridges on the dorsal surface, with which it moves round and round when touched. Anthrax nigricosta is a handsome little black fly, with the head, under surface of the body, and two bands across the abdomen fringed with white down. The wings are deeply marked with black on the front margin, widest at the base. It measures about ½ an inch in length, and comes from Queensland. Comptosia albo-fasciata is a large black fly shaded with fine reddish hairs on the dorsal surface of the body; the wings are brown, very long, with white tips; the body measures about ¾, and across the outspread wings 1½ inches. Neuria quadripennis is a much smaller, but somewhat similar looking fly, with the dorsal surface and margins of the body more hairy; each wing is darkly clouded, with the base light, and the tip white. Both these species are not uncommon in New South Wales.

Acreotrichus gibbicornis is a beautiful little black fly with brown eyes; not much over ¼ of an inch long; the elongate antennae and head are clothed with tufts of black and white down; the rest of the body is enveloped in long silvery white down. A. fuscicornis is of a rich violet black tint, a yellow line round the hind margin of the head, and a broader band round the dorsal margin of the thorax of a similar colour; the broad rounded abdomen is lightly banded with pubescence. These flies were taken in numbers hovering over the flowers of plum-trees in an orchard near Sydney.

Family 9. Bladder Flies.
ACROCERIDAE.

These are very curious looking flies with such very small round heads, that at first sight one would think that they were broken off; but on closer examination the little knobs in front will be found to consist of two large eyes joining together on the inner edge, with small, 2 or 3 jointed antennae. Nothing is known about the larval habits of our species, but in Europe they are parasitic on spiders or their cocoons.

The members of the Genus Pterodontia have the body inflated like a bladder; we have several species in Australia, generally found resting on twigs or tree trunks. Pterodontia mellii measures under ½ an inch in length; the thorax and body are swollen out like a bladder; it is of a general black colour, with a mark on the back, the fore legs, and a large blotch on either side of the body bright ochreous yellow; but the dark portions are thickly clothed with fine black downy hairs like a bumble bee. The wings on account of the swollen body look much smaller than they really are. I have specimens from Queensland, and Hunter River N.S.W., and they probably have a wide range.

Panops flavipes is a very curious looking fly from Moruya, N.S. Wales, measuring over ½ an inch in length; it is of a general dark bronzy black tint thickly clothed with fine down, silvery on the tip of the abdomen. The head is very small, black and shining, with the thickened cylindrical antennae standing out in front; the thorax, swollen out behind the head, has a large angular white patch on either side; the abdomen not quite as thick as the thorax is deeply corrugated. The wings have the front half deeply clouded and the hind portion transparent.

Acrodes fumatus is a much smaller species about ⅕ of an inch in length; the head and thorax are black; the bladder shaped abdomen is tawny yellow, with parallel stripes of black down the centre and sides, and transverse white bars at the apex of each segment. They were collected in numbers about Cook’s River, near Sydney.

Family 10. Mydas Flies.
MYDAIDAE.

These might be called “mimic flies,” because, with their large thickened antennae (often swollen out into a compressed club at the tips), their broad heads, elongated bodies, and bright variegated black and yellow markings, they can be very easily mistaken at first sight for Pompilid wasps. The mimicry is further emphasised by the thickened spined legs, and coloured wings.

We have a number of species in Australia; they are allied to the “Robber-flies” which some of them resemble. The larvae of foreign species are predaceous, feeding upon the grubs of various wood-boring beetles.

Mydas fulvipennis has the greater part of the head, thorax, under surface of the abdomen, and thighs black; with the face, antennae, legs, wings and rest of the abdomen except two indistinct narrow bars, bright reddish yellow. It measures over ¾ of an inch in length, and is of the usual elongate robust form with long clubbed antennae and thickened legs. My specimens come from Southern Queensland.

Plate XXVIII.—DIPTERA.

Family Muscidae.

1. Chaetogaster violacea (Macq.).

Family Tabanidae.

Family Asilidae.

Family Diopsidae.

4. Zygotricha sp.

Family Bombylidae.

Family Dexiidae.

(Original photo. Burton.)]

Family 11. Robber-flies.
ASILIDAE.

This group is well represented in Australia by some very large handsome robber-flies which attack and kill many insects larger than themselves, transfixing them with their horny bayonet-like proboscis. The large projecting eyes forming the greater part of the head are well separated from the thorax; the three jointed antennae stand out at an angle from each other; the legs are long, stout, and covered with stiff hairs well adapted for holding their prey; they have more or less clouded wings; and a slender, rather cylindrical body tapers to a blunt tip in the female, but in the male terminates in a pair of pincer-like processes. It is an extensive family, over 3,000 species being described from all parts of the world; they are very numerous in America, where one is a very serious pest to honey bees. Their larvae live in the ground and are predaceous, feeding upon the larvae of other insects, particularly those of beetles.

The members of the Genus Dasypogon are small delicate flies that cling to grass stalks, and are easily taken with a sweeping net; they have the typical form of the family, and their slender bodies taper to a point. Laphria diversipes is a common insect about Sydney often taken on fences; it is slightly over ½ an inch in length; its general colour is black, with stout reddish brown legs variegated with black. The head is clothed with stiff grey hairs, the upper surface mottled with golden pubescence, and scattered black hairs. Laphria rufifemorata is a somewhat large insect from Queensland, with the abdomen of a deep metallic blue. Leptogaster geniculatus is a remarkably slender bodied fly, about the same length, found about the Blue Mountains N.S.W. The head is short but wide across; the thorax is oval, and the linear abdomen swells out slightly to the apex; the legs are long and slender, the hind pair with the thighs swollen in the centre. The general colour is shining black with the legs marked with white.

The typical Genus Asilis contains some handsome flies generally met with in open forest country: Asilis inglorius, over 1 inch in length, has large black eyes; the front of the head is clothed with grey bristles; the thorax is olive green, marbled with grey pubescence, thickest on the ventral surface; the legs are red, the tarsi black; and the wings are clouded with yellow; the abdomen is much elongated to the pointed tip, reddish brown, the first 3 segments thickly clothed with long, pale, golden, downy hairs, and with the terminal segments covered with very short reddish brown hairs. A. plicatus is slightly larger, of a general greyish brown tint, with pale reddish brown markings on the thorax; the legs are darker brown; the abdomen is lightly clothed with fine scattered grey hairs. A. fulvitarsus is a much smaller species of a somewhat uniform buff tint, inclined to a golden tint on the lower portion of the abdomen; the face is clothed with grey and buff hairs, and the wings are light brown.

Blepharotes splendidissma is a very handsome fly with the abdomen flattened, broad, and almost heart shaped; it measures nearly 1½ inches in length, and 2½ across the outspread wings. It is of a general black colour with the abdomen of a shining bronzy green tint; the face is clothed with yellow bristles; the thorax has grey pubescence on the sides, and the outer margins and tip of abdomen are fringed with tufts of yellow and black downy hairs. I have frequently captured it flying about in the Botanic Gardens, Sydney, in the early summer. Phellus glaucus is a very curious fly found in the interior of Western Australia; it measures nearly 2 inches from the front of the head to the tip of the wings; a great tuft of bright yellow hairs stand out in front of the head; it is thickly clothed on the under-surface of the head with pale yellow hairs; the legs are very stout and hairy, and clothed with black down marked with white and large yellow tufts on the hind legs. The abdomen is thickened, elongated and broadly rounded to the tip, of a uniform deep metallic blue tint, but so thickly clothed with short black down that its rich colour is somewhat obscured. Craspedia coriaria is one of our largest robber-flies, widely distributed all over the interior of the continent; its mouth is produced into a stout pointed awl-like process, with which it can pierce the integument of the stoutest insect, and it can be often seen flying along with its beak buried in the back of a large cockchafer beetle (Anoplognathus), and with its large legs clasping its victim as it sucks up its blood. Its general colour is black, with the broad, flattened, more elongate abdomen thickly clothed with short brick-red hairs; the legs and under surface are very hairy, with tufts of stiff black hairs fringing the outer edges of the abdominal segments. The wings are opaque and almost black, with an expanse of about 3 inches.

Saropogon princeps, described by Macquart, has a large reddish brown wasp-like form that at first sight might be easily mistaken for a Pompilid wasp. It measures 1½ inches in length, with a wing expanse of about 3 inches. The head, under-surface, centre of the thorax above, the basal segment, and two bands on the abdomen are black; the rest is dull red, with the hind margin of the wings hyaline. I have a specimen from Mittagong N.S. Wales. Brachyrhopala ruficornis comes from Mackay, Queensland, and has a very wasp-like appearance both in the colouration and shape of the body. It is under ½ an inch in length with the typical robber-fly head and spiny legs, but the abdomen is contracted into a cylindrical waist behind the thorax, rounded in the centre, and tapered to the tip. The head and thorax are almost black; the hind margin of the latter and legs are dull red; the abdomen is dull yellow with the basal segments marked with blackish brown, forming two almost confluent bands round the broad centre.

Family 12. False Robber-flies.
APIOCERIDAE.

These flies are of medium size not unlike Muscidae, with large elongated bodies, short antennae, and clear wings. This is a small family containing two genera, the species of which are peculiar to North America, Chili, and Australia.

Apiocera bigotii, described by Macquart, is about ¾ of an inch in length; it has a short head not so wide as the thorax, with a long projecting proboscis; the elongate broadly rounded thorax is truncated behind; the abdomen is broadest in front, rounded, and tapers to the tip, which terminates in a tuft of fine spines. The wings are somewhat iridescent with reddish veins; the general colour of the fly is a dull brown, with white hairs and silvery pubescence clothing the hind portion of the head and under-surface of the thorax, and also mottling the dorsal surface of the body with grey. Some specimens in my possession come from the Shoalhaven district. Apiocera asilica described by Westwood is a larger much darker insect, with black hairs on the upper surface and grey on the under surface; it ranges from Queensland to the Blue Mountains N.S.W.

Family 13. Big-eyed Flies.
PIPUNCULIDAE.

These are tiny little creatures with very large heads consisting almost entirely of two great hemispherical eyes. The short antenna terminates in a bristle.

About 80 species had been described, chiefly from Europe, until Perkins published the descriptions of 26 species from Australia (Leaf Hoppers and their natural enemies Pt. iv. Pipunculidae) Hawaii 1905.

They are remarkable for their habits in the larval state, being parasitic upon the larvae and pupae of frog-hoppers, chiefly Jassidae, particularly those Homoptera that have the tip of the abdomen clothed with waxy filaments. When full grown the dipterous larvae leave their host and bury themselves in the soil, where they pupate. Mr. Koebele allowed me to examine the collection he made of these little flies before they were described by Mr. Perkins. Many of these he reared from infested frog-hoppers in Queensland when studying sugar-cane pests.

Pipunculus helluo was observed swarming round the larvae of Siphanta, which were abundant on fig trees near Bundaberg Queensland; this species was also taken by Koebele near Sydney. P. cinerascens is remarkable in the larval form, as it does not fall to the ground and pupate in the soil, but forms its puparium upon the surface of the living leaves in the open. P. cruciator comes from the district of Cairns, N. Queensland.

Family 14. Hover Flies.
SYRPHIDAE.

Several species are well known and common in gardens, where they are popularly known under the name of “Bee” or “Hover Flies” from a way they have of poising, apparently motionless, over flowers and aphid-infested bushes, for the movement of their wings is so rapid as scarcely to be detected. The perfect flies, which among the carnivorous species have slender bodies more or less barred or banded with yellow, lay their eggs upon aphis-infested plants; the young larvae emerging from the white eggs feed exclusively upon aphids and plant lice; the full-grown larva is legless, very elongate in form, and has great powers for extending and contracting its abdominal segments, so that the body, from a rounded mass, can extend into a long and slender form. The full-grown larva pupates in an oval hard chrysalid which usually falls to the ground.

The typical Genus Syrphus is well represented in Australia by several fine species, all of which are aphid eaters, and fly about in the bright sunshine but shelter among the foliage at other times; whenever aphis appear the syrphid flies soon follow, and I have seen them round the aphid-infested briar bushes in countless thousands. Syrphus pusillus, figured in the Agricultural Gazette N.S.W. 1904 under the name of Syrphus viridiceps, is our commonest species found upon aphis-infested rose bushes, orchard trees, and wheat fields. It measures about ⅓ of an inch in length; has large reddish eyes, yellow face, and dull metallic green thorax with yellow scutellum; the darker abdomen is banded with three interrupted transverse yellow bands, and smaller marks on the apical segments. S. viridiceps is a more slender form, with a green face; the whole of the thorax is shining lead colour, with fine yellow bands on the abdomen; the legs are dark, and the whole fly is lightly clothed with fine hairs. Both these species may be taken on the same bush, and both have a very wide range over Australia.