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larva living in rotten fungi. S. Niger, Deg. Curt. 609 (rugosus).

20. Cyrtida. This unique group, till quite recently known as the Acrocerida, is also a limited and natural one, being allied to some genera of Bombylidæ. Small, soft, globular flies, the abdomen being apparently filled with air, splitting open with the least touch; head nearly all eye ; thorax very convex ; venation very indistinct, and confined principally to the upper portion of the wing ; legs very short ; sluggish in nature; found on tree trunks and flowers, or floating about in the breeze on calm, sunny days; long 4-5 mm.

Oncodes gibbosus, L., is selected by a species of Crabro, which burrows in wood, as the food for its young.

Only two genera are British, each represented by a single species.

Third longitudinal vein forked : Paracrocera, Mik. Third longitudinal vein simple: Oncodes, Latr. Paracrocera globulus, Pz., Wlk. Pl. i. 16.

the earth, the latter in some species being spined. About thirty species are British, appearing chiefly in the spring ; the are very voracious.

E, livida, L., is a long brown fly, with three longitudinal black stripes on the thorax ; long pale tawny legs, with black tips to tarsi and tibiæ, and very pale brown or quite clear wings; common; long 8-9 mm.

E, tessellata, F., is allied to the above; rather stouter and larger, legs darker brown ; thorax with three black stripes ; abdomen marked with a light spot in the centre of, and joined to a light posterior border to, each segment; wings brown; long 9 mm. Macquart observed one species (O. opaca, F.) emerge

from the pupa.

are

21. Empida, About 160 species of this extensive family are British. Their habits

very various, they frequenting woods, ditches, fields, and the banks of streams, some having the power of running over the surface of the water. Head small; body attenuated ; legs long and slender ; posterior femora in o in some genera much enlarged.

Some inhabit the coast, a few frequent flowers, running with great swiftness over the leaves and herbage. Many species are common, some abundant, often for a few days only, and while swarming, fly backwards and forwards in streams, moving as by a common impulse.

The venation varies in the several genera ; mostly carnivorous (especially the 4, the of often feeding on the juices of plants), small Diptera, and Ephemerida appearing to be their chief prey.

Westwood illustrates the larva of one or two species. Five sub-families are recognised, all being represented in Britain. Anal cell present. Anterior coxæ shorter than femora.

Proboscis long: third longitudinal vein forked: Em.

pina.
Proboscis short ; third longitudinal vein simple.

Anal cell longer than lower basal cell: Hybotina.
Anal cell shorter than lower basal cell: Ocy.

dromina.
Anterior coxæ very prominent; as long as, or longer than,

femora: Hemerodromina. Anal cell absent: Tachydromina.

Hybotina.-Hybos grossipes, L., is a small shining black fly with black legs, the posterior femora being enlarged in the o. Flight slow; it usually hovers in swarms on summer evenings. Long 43 mm. Cyrtoma, Mg., inhabits trees and woods in summer.

Empina.-Empis, L. The larva and pupa live in

Rhamphomyia, Mg., allied to Empis ; apical transverse nervure wanting ; twenty species British, their habits being similar to those of Empis.

Pachymeria femorata, F., is a small black fly with pale brown wings and black stigma; black legs with the two posterior pairs with dense black fringe on femora and tibiæ ; long 4-5 mm.

Hilara, Mg. Many species of this extensive genus are met with on summer evenings, swarming over streams.

H. maura, F., is a small shining black fly with black legs and pale grey wings; black along the fore border and with black stigma. I could have taken ten or twelve thousand specimens of this species one day at Staines, where it swarmed over a shallow stream. It is very common ; long 4 mm. The species (twenty are British) are closely allied. The anterior tarsi in many species are dilated in the .

Ocydromina.—About six or eight species are British.

Hemerodrominæ.-Hemerodromia, Mg., inhabits grass, shrubs, and moist situations; their flight is slow; their fore-legs enlarged ; long 3-5 mm.

Clinocera, Mg., a genus of slenderly-built flies, of which we have nine species ; inhabits moist localities.

Tachydromina.— Tachydromia, Mg., an extensive genus, is represented in Britain by about thirty species, occurring in marshy situations ; their movements are very agile, running swiftly over the leaves. This species are widely distributed.

H. grossi pes, L., Curt. 661 (pilipes). E, livida, L., Curt. Farm insects, Pl. J. 5. E. borealis, L., Curt. 18. Ragas unica, Wlk., Wlk. iii. 3. Clinocera stagnalis, Hal., Wlk. jii. 6.

22. Dolichopidæ. About one hundred and sixty species of this family are indigenous. Two very excellent monographs on the genus Dolichopus, Latr., have been published by Stannius (1831), and Staeger (1842).

The Dolichopide are rather small flies, usually of a metallic green or bronze colour, with long, spiny legs, very brittle in character.

The wings are generally clear, the abdomen usually conical, shining.

8. Psilopus Weidemanii, Wlk., i. Pl. vi. 1. Cam. psicnemus scambus, Wlk., i. Pl. vi. 6. Porphyrops elegantılus, Curt., 541. Scellus notatus (Hydrophorus), Curt., 162.

23. Lonchopterida. A limited group of small active flies, inhabiting grassy marshes and such like habitats, being found during the greater part of the warm weather. About half a dozen species are British, two being tolerably common, L. lutea, Pz., the commonest, being yellowish-brown with black antennæ and eyes, a black spot on the vertex of the head and the centre of the front of the pronotum ; a brownish-black vertical stripe on the abdomen (variable); a thin central brown line on the thorax, and dark tarsi.

Lonchoptera lutea, Pz., Wlk., vol. i. Pl. viii. 1.

and shortly pubescent. Many species are common ; they occur chiefly on hedges and in grass, on the stems of reeds, and plants of low growth. The abdomen at the tip curls inwards in the majority of the species.

Psilopus, a genus of delicate, long-legged flies ; congregates in small groups in shady spots.

Dolichopus, Latr., sound in marshy ground and long grass, in rank herbage and about overgrown pools; a few species occur on the sea-coast. Degeer has observed the transformations of D. ungulatus.

Dolichopus trivialis, Hal., metallic green; face above antennæ green, below whitish ; antennæ black ; wings pale grey ; legs livid or pale yellow; tarsi black; tibiæ spiny ; com on; variable; long 4-5 mm.

Poecilobothrus nobilitatus, L., brilliant metallic green; under-side of thorax with silvery-grey reflections; face silvery below, green above ; antennæ, which are black ; legs pale yellow; tips of posterior tibiæ, and all tarsi black; wings clear; a large brown streak near the tip extending from fore to hind border ; not uncommon ; long 5 mm.

Diaphoris, Mg., and Chrysotus, Mg., very small and uncommon fies, metallic in colour, occurring on trees in the hot sunshine.

Argyra, Mcq., conspicuous by the whitish pubescence on the abdomen in some of the species; generally distributed.

Argyra diaphana, F., thorax blackish ; dorsum me. tallic green ; abdomen greenish-black ; sicles of first two or three segments pale yellow, and from the second segment to the tip, with whitish tomentum ; face and antennæ black; wings pale grey; legs blackish-brown, tibiæ lighter; not uncommon ; variable. The ground colour and markings of the abdomen resemble those of Homalomyia caniculata ; long 6 mm.

Porphyrops, Mg., about twelve species-some not uncommon.

Hydrophonis, Whlg. This, with Medeterus of Fisch, are carnivorous genera (Doubleday and Macquart both record having watched them devour small insects.) The former inhabits the surface of pools ; the latter frequents dry, warm localities, and is conspicuous by its bulky proboscis.

Thinophilus, Whlbg., three species ; rare; sea. coast.

Scellus notatus, F., metallic bronze; sides of thorax with whitish reflections ; face brown or black; whitish below antennæ ; antennæ black; wings with brown streaks along the veins, and a distinct brown spot on fourth longitudinal vein near the tip ; legs blackish ; a few scattered spines; not rare; long 53-6 mm.

Campsicnemus, Wlk., found in damp grass, occuring during the greater part of the year. C. scambus is not rare.

The following plates are good :--Argyra leucocephala, Wlk. i. Pl. vii. 4. Medeterus diadema, Wlk. i. Pl. vii.

24. Platypezida, All the four European genera of this family are British, representing about a dozen species, all more or less uncommon, inhabiting woods, the larvæ living in fungi.

Van Roser has published his observations on P. boletina, Fall., the larva of which lives in rotten mushrooms, and resembles a seed. Westwood figures it in his “Class. Ins.,” vol. ii. Fig. 130-17. Walker illustrates P. picta, Mg., “Br. Dip.”i. Pl. viii. I, and Callomyia elegans, Mg., Pl. viii. 3.

Curtis gives a good plate of Opetia lonchopteroides, Curt., in his “Br. Ent." 489; mostly shining black flies, about 4-5 mm. long. The genera may be recognised as follows:Discal cell present.

Fourth longitudinal vein simple: Callomyia, Mg.

Fourth longitudinal vein forked: Platypesa, Mg.
No discal cell.

Fourth longitudinal vein simple : Platycnema, Lett.

Fourth longitudinal vein forked : Opetia, Mg. Platypeza picta, Wlk. i. Pl. viji. I. Opetia lonchopteroides, Curt. 489.

25. Pipunculidia. Allied to both the Platypezida and Syrphide (to the latter, through the sub-family Bacchina). Three genera are European, two being British. They inhabit fields and woods, and are in the habit of hovering in the air ; they are not difficult of determination, but none can be said to be common. They are larger than the Platypezide, and more stoutly built.

Discoidal cell present: Pipunculus, Latr.

Discoidal cell absent: Chalarus, Wlk. Pipunculus pratorum, Fall., Curt. 757. Chalarus spurius, Fall., “ Br. Dip.” i. Pl. viii. 7.

26. Syrphida. This extensive and well-known group is divided into several sub-families, and represented in Britain by over 200 species (about 1100 species are European).

As a rule the species of this family are flat-bodied,

brightly coloured insects (usually more or less yellow

7-9 mm.

The commonest species are S. ribesii, L., and black), many resembling wasps ; and they are corolla, F., pyrastri, L. ; larva figured by Westwood, popularly known as drone flies or sun-flies, from their Class, Ins. ii. Fig. 130-21. Baltcatus, Deg., habit of hovering in the sun over flowers, emitting Bouché has observed the metamorphoses of this meanwhile a shrill hum ; their movements on the species, and luniger, Mg. The larvæ of this genus wing are very rapid, and, so to speak, spasmodic. feed on Aphida.

The larvæ feed on a variety of substances, some on Platychirus, St. Farg., an allied genus of about decaying vegetable matter, these being thus of con- twelve British species, has a narrower abdomen, siderable assistance to agriculturists, the flies being several species being common; about the length of, so abundant.

and closely resembling Syrphus. The venation in Schiner divides the Syrphidæ into eight sub. Syrphus, Platychirus, Chilosia, and Melanostoma is families : Syrphine, Volucelline, Sericomyina, Eris. very similar. Mr. Verrall, in the "Ent. Mon. Mag.," talina, Milesina, Chrysotoxina, Microdonina, Cerina ; gives some excellent notes on the British species but Verrall neither recognises sub-families in his list, of Platychirus. nor adheres to the German author's sequence of Chilosia, Mg., a rather large genus of black flies, families.

more or less pubescent, rather stoutly built ; wings The Pipiza group of genera seem to me appro- never marked, and generally grey or brown. Chiefly priately placed next the Pipunculidu, and the Cerina found in woods and meadows, and most of the species undoubtedly approach the Conopide, which latter are more or less local ; long about 8-10 mm, A family form a useful intermediate group to connect continental authority (Professor F. Kowarz) has the divisions of Macquart's Tetrachætæ and Dichæta, recently revised the majority of the European species. The principal genera may be tabulated thus :

Rhingia rostrata, L., a characteristic species; tawny Marginal cell closed.

brown, with a black head and thorax ; tawny face Antennæ plumose : Volucella, Geoff.

produced in the form of a strong, long, pointed Antennæ with a bristle: Eristalis, Latr. Marginal cell open.

snout ; wings pale grey ; legs tawny ; proboscis long Posterior femora thickened. Third longitudinal vein straight.

and horny ; common ; long 7-8 mm. Reaumur found
Fourth longitudinal, before its junction with third, bent the larva in cow-dung.
into two loops.
Fourth longitudinal at second loop bent back to Eristalis, Latr.—These are the typical “drone

the third: Eumerus, Mg.
Fourth longitudinal at second loop carried for.

Alies,” several species being very common, the larvæ wards to the third: Syritta, St. Farg.

living in stagnant water.
Fourth longitudinal vein, from the portion bent up to
its junction with third, nearly straight, and more or

E. tenax, L., is a brown fly, with grey or pale less in a straight line with the bent-up portion of the

tawny marks on the abdomen ; face clothed with Eyes bare.

short, pale yellow pubescence, with a strong, broad, Abdomen conical or rounded. Arista bare: Criorhina, Mcq.

central black line ; legs brown, paler at the knees and Arista plumose: Sericomyia, Mg.

tips ; wings clear, or slightly brown at the base, foreAbdomen elongated : Xylota, Mg. Eyes hairy: Pipisa, Fall.

border, and towards the tip ; thorax clothed with Third longitudinal vein strongly looped downwards into first posterior cell: Helophilus, Mg.

short thick tawny brown pubescence ; abdomen very Posterior femora normal.

variable in colour, sometimes entirely black; very
Antennæ elongated-longer than head-horizontal:
Chrysotoxum, Mg.

common everywhere ; long 10-12 mm.
Antennæ normal-shorter than liead-deflexed.
Abdomen much retracted at basal segments :

I once placed a live o in a glass-top box with a
Baccha, F.

dead ? and it remained in côp. for about half an Abdomen barely or not retracted at base. Eyes pubescent; wings spotted.

hour.
Abdomen golden yellow : Chrysochlamys, E. intricarius, L., abdomen thickly clothed with

Abdomen blackish blue: Leucocona, Sch. black hair, tip with whitish hair ; base of the tibia
Eyes bare; wings never marked.
Species yellow and black.

pale yellow ; wings clear ; scutellum surrounded by Abdomen elongated-longer than wings: thick yellow hair ; thorax clothed with black hair ;

Sphærophoria, St. Farg.
Abdomen oblong or oval-shorter than rather smaller, less common, and more local than
wings.

tenax. The colour of the pubescence varies greatly, Anterior tibiæ in dilated; abdomen

oblong: Platychirus, St. Farg. being sometimes nearly all yellow, or with a reddish
Anterior tibiæ never dilated ; abdomen
oval: Syrphus,, F.

tinge ; long 8-9 mm.
Species black or greenish-black.

E. arbustorum, L., a very common species, smaller
Front rough or furrowed: Chrysogaster,
Mg.

than intricarius ; abdomen bare, tawny with, roughly Front smooth: Chilosia, Mg.

speaking, two black triangular spots on it, their Syrphus, F. This, the commonest genus, is repre- apices nearly touching ; legs black and yellow; sented by about thirty-five rather closely allied wings clear; thorax with greyish yellow pubesence ; species, all more or less resembling wasps. Abdo- face with yellowish white hair ; frontal stripe in ? men bright yellow, with transverse black stripes ; black; long 8 mm. ; very common everywhere ; thorax yellowish, greyish, or livid ; legs thin, yellow variable. with black rings ; wings usually clear ; long about Volucella bombylans, L., a large bee-like fly covered

fifth.

Rond.

12.

with thick pubescence, which is yellow on the thorax, Chrysotoxum, Mg.-Seven species are British. A black at base of the abdomen, and whitish or reddish genus of large, handsome, wasp-like flies, except that at the tip, and two yellow tufts of pubescence at the the base of the abdomen is not contracted ; thorax sides of the base of the abdomen ; under side of black, with yellow side markings ; face black, thorax with thick black hair ; face with yellow hair, generally with a wide central black line; abdomen: and in 9 with a central stripe of thick yellow hair ; oval, convex, yellow with transverse black markings ;. legs black ; wings pale grey, brownish tinged along legs thin, principally yellow; wings unmarked, greythe fore border'; very variable. There are two ish; base tawny yellow; long 10-12 mm. Larva distinct varieties, both of which Miss E. Ormerod feeds on plant roots. has bred from one-batch of eggs; and Mr. Verrall The Syrphida occasionally swarm in countless. possesses a series, showing every form of intermediate numbers, when several species are sometimes found colouring ; common ; long 9-11 mm.

forming part of the host. At Margate, in August, V. pellucens, L., a large black fly; bare ; basal half 1869, the following appeared in vast profusion during of abdomen livid ; legs black; wings nearly clear, one day :-E. tenax, S. balteatus, and Spharophoria with a large irregular blackish spot in the centre of taniatus. the fore border, extending downwards half way across Swammerdam and Reaumur have studied and the wing ; face yellow; slightly smaller than bomby- illustrated their writings on the life-histories of lans; common.

several common species. Helophilus pendulus, L., a yellow fly; bare ; top Over a thousand species are European. Sphegina of thorax black, with four yellow stripes ; abdomen clunipes, Fin., Wlk. i. Pl. X. 16. Syrphus pyrastri, with transverse black markings; face yellow, with L., Wlk. i. Pl. X. 12. Leucozona lucorrum, L., Curt. a central black line ; legs black and yellow ; posterior 753. Rhingia campestris, L., Curt. 182. Volucella femora enlarged; wings clear ; rather common ; inflata, F., Curt. 452. Sericomyia borealis, Fln., long 9-10.

Walk. Pl. ix. 14. Syritta pipiens, L., Wlk. Pl. ix. 9. Several other species of Helophilus are more or Criorhina oxyacantha, Mg., Wlk. Pl. ix. less common in Britain ; mostly yellowish in colour, Chrysotoxum bimaculatum, Curt. 853. and allied to pendulus ; known as “sun-flies," their habits being similar to those of Eristalis.

27. Conopida. Xylota segnis, L.-Black, basal half of abdomen

This group is a small one, allied to both the dull red; face with short whitish pubescence; legs Syrphide and higher forms of Muscida. The species black, with base of tibize yellow; wings grey or pale in the first division closely resemble wasps (Odynerus, brown; posterior femora enlarged ; long 8-9 mm. &c.); the larvæ are parasitic on bees, Latreille About six species of Xylota are British. The larva having reared P. rufipes from living Bombida, whilst. of Xylota lives in decayed wood,

Westwood noted the abundance of O. atra on sand. Syritta pipicus, L., is a small and very common banks in which several species of bees burrowed. insect found everywhere, London included. Black, One or two authors have greatly multiplied both with the under side grey ; face with thick greyish genera and species, nearly all their names being now whitc pubescence, a small yellowish spot at each

sunk as synonyms. The eyes are wide apart in both edge of posterior borders of the abdominal segments; sexes, the & being distinguished by a ventral horny legs black, marked with tawny or yellow; posterior

process towards the end of the abdomen. femora much enlarged ; wings quite clear : variable None of the species can be said to be common. in size and markings. Larva lives in horse-dung;

Antennæ stylate; ocelli absent (Conopine). long 5-7 mm.

First abdominal joint of normal width : Conops, L. Criorhina oxyacantha, Mg., resembles a bee;

First and second abdominal joint much retracted: Phy

socephala, Sch. covered with yellow pubescence, deepest in colour on

Antennæ with a bristle ; ocelli present (31 yopinæ).

Proboscis bent only at the base : Zodion, Latr. the thorax ; face much produced ; black, covered on

Proboscis bent at the base and at the middle. upper side with thick yellow hair ; legs all black or

Face much produced downwards below the eyes ;

proboscis short: Myopa, F. dark brown ; wings pale grey, yellowish at the base,

Face not much produced downwards below the

eyes; proboscis long: Oncomyia, and with a black stripe extending. half way across the wing from the centre of the fore border. The larva Conopina.-Conops favipes, L., is black and lives in river bank mud ; long 12-13 mm.

yellow ; face yellow, with a central black stripe ; Eumerus, Mg., a genus allied to Syritta, is repre

antennä black; thorax black, with yellow spots on sented by three species.

shoulders ; abdomen black, with two (2) or three Chrysogaster, Mg., is a genus of metallic, dark, (0) yellow bands; legs yellow and black ; wings. greenish-black flies, with rather dark wings; black greyish ; fore border brownish ; long 10 mm. This legs, short pubescence; several species, all closely is the most common species of the genus. allied, are British ; one of their characteristics is the Phyrocephala rufipes, F.-Phyrocephala is dis. grooved face; they appear chiefly in spring and tinguished from Conops by the first and second summer on Ranunculi ; long 6-7 mm.

abdominal segment being much contracted ; the legs

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are thinner, and have frequently a twisted appearance. The colour of P. rufipes is brownish red; face yellowish, with a black central stripe; antennæ black; legs tawny brown, marked with black; wings pale grey, anterior portion pale brown almost to the tip ; tip of abdomen covered with thin silvery-grey tomentum, and it varies in colour ; long 10 mm.

Myopina.-Sicus ferrugineus, Scop.; rather common and widely distributed. Uniformly tawny; face broad-reddish-yellow; wings pale grey, tinged with tawny ; long 6-8 mm.

Myopa testacea, L., is tawny ; dorsum of thorax black, with greyish reflections ; wings pale tawny grey ; internal transverse vein clouded ; under side of face white ; pubescent; rather common, and enerally distributed ; long 5-7 mm.

M. buccata, L., an allied and rather common species, has pale brownish marks on the wings, giving them a mottled appearance, and the transverse veins are not distinctly clouded. Stomoxys, a genus of Muscida, has erroneously been included in this family.

Conops flavipes, L., Panz. lxx. 21. Physocephala rufipes, F., Wlk. i. Pl. x. 18.

I
NOW come to a genus of testaceous Rhizopods,

viz., Diffugia, so common, and so widely distributed, that every microscopist is more or less familiar with their arenaceous, box-like shells. Every pond, ditch, and bog is sure to furnish one or more species of this ubiquitous genus, if the sediment be carefully examined ; and it is somewhat comical to see the box-like shells, especially the taller species, bobbing about among the Algæ and broken-down organic detritus. The genus contains about twelve. species--differences in form of shell or test, and in the character of the mouth, separating them. These species, however, are often connected by intermediate forms, and it is sometimes very difficult, and more rarely impossible, at the time, to say definitely to which species a given specimen may belong, as it may possess the characters of at least two species, in fairly-balanced proportions. They present themselves

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28. Estrida. The Estridæ form a small but very interesting group, represented by eight British species. In the imago the mouth is obsolete, the venation more or less obscurely defined, and the alulæ large ; eyes widely separated in both sexes. In the larval state they are parasitic, each species living on or in a different animal, the larva dropping to the earth when fully developed, and pupating in the ground.

In Gastrophilus equi, F., the g lays her eggs in the mane of the horse, and on the animal licking it, the eggs pass into the stomach, where the larvæ emerge and develop, afterwards passing out with the dung, and pupating in the earth. The imago is a brown fly, with yellow and brown pubescence ; the face is covered with yellow pubescence ; the legs are thin, yellow, somewhat short ; the wings grey, with a dull brown stripe in the centre; the abdomen has yellowish pubescence. Long 11-12 mm.

Oestris ovis, L. The lays her eggs on the nose of the sheep, the larvæ crawling thence into the head, where they attain their full size, afterwards descending the nostril, and assuming the pupa state in the ground.

It is a brownish-grey fly, with clear wings, large white alulæ, and yellowish-brown legs; long 9-10 mm. When attacked, the sheep cluster in a circle, Tholding their noses together close to the ground.

Hypoderma bovis, Deg., is parasitic on cattle, laying its eggs in the back, a tumour arising, from which when full grown the larvæ emerge. Black, pubescent ; tip of abdomen with red pubescence ; face and under side with grey pubescence; legs black; wings brown ; long 12-14 mm.

as round, oval, pyriform, or in other ways elongated, box-like shells, made up of large and small sand. grains and diatom frustules (chiefly of the linear kind), separately or mixed in various proportions ; in more than one species it is of chitinoid membrane, and especially is this the case in the forms from Sphagnum. Indeed, I believe that in all the species there is a chitinoid basis, even in those species in which nothing but sand-grains can be seen. They vary greatly in form and size, not only among themselves, but in the same species. I have seen a D. acuminata as large as the as of an inch in height; other and rounder species are as small as the top of an inch in diameter ; but from tho to zoo of an inch may be considered as ordinary dimensions. The sarcode is occasionally coloured, more commonly green, and

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