HARD WICKE'S SCIENCE- G OSS IP. 



129 



brightly coloured insects (usually more or less yellow 

 -and black), many resembling wasps ; and they are 

 popularly known as drone flies or sun-flies, from their 

 Tiabit of hovering in the sun over flowers, emitting 

 meanwhile a shrill hum ; their movements on the 

 wing are very rapid, and, so to speak, spasmodic. 



The larvDs feed on a variety of substances, some on 

 decaying vegetable matter, these being thus of con- 

 siderable assistance to agriculturists, the flies being 

 so abundant. 



Schiner divides the SyrphidiS into eight sub- 

 families : Syrphimv, VolucelHtm, Sericomyimv, Eris- 

 talinir, Milcsiua, Chiysotoxifur, Microdonitur, Ceriucr ; 

 but Verrall neither recognises sub-families in his list, 

 nor adheres to the German author's sequence of 

 families. 



The Pifiza group of genera seem to me appro- 

 priately placed next the Pipimculidic, and the Ceriiia: 

 undoubtedly approach the Conopidcv, which latter 

 family form a useful intemiediate group to connect 

 the divisions of Macquart's Tctrachivta: and Dickcvtc^. 



The principal genera may be tabulated thus : — 



Marginal cell closed. 



Antennae plumose : Volucella, Geoft". 

 Antenna; with a bristle : Erisialis, Latr. 

 ^Marginal cell open. 



Posterior femora thickened. 



Third longitudinal vein straight. 



Fourth longitudinal, before its junction with third, bent 

 into two loops. 



Fourth longitudinal at second loop bent back to 



the third : Eiimerus, Mg. 

 Fourth longitudinal at second loop carried for- 

 wards to the third : Syritta, St. Farg. 

 Fourth longitudinal vein, from the portion bent up to 

 its junction with third, nearly straight, and more or 

 less in a straight line with the bent- up portion of the 

 tifth. 

 • Eyes bare. 



Abdomen conical or rounded. 



Arista bare : Criorhina, Mcq. 

 Arista plumose : Sericoiiiyia, Mg. 

 Abdomen elongated: Xylota, Mg. 

 Eyes hairy : Pipiza, Fall. 

 Third longitudinal vein strongly looped downwards 

 into first posterior cell: Helophilus, Mg. 

 Posterior femora normal. 



Antennae elongated — longer than head — horizontal : 



Chrysotoxum, Mg. 

 Antennae normal— shorter than head— deflexed. 



Abdomen much retracted at basal segments : 



BaccJia, F. 

 Abdomen barely or not retracted at base. 

 Eyes pubescent ; wings spotted. 



Abdomen golden yellow : Chrysochlamys, 



Rond. 

 Abdomen blackish blue : Leucozoua, Sch. 

 Eyes bare ; wings never marked. 

 Species yellow and black. 



.A.bdomen elongated — longer than wings : 



SpJuErophoria, St. Farg. 

 Abdomen oblong or oval — shorter than 

 wings. 

 Anterior tibiae in cT dilated ; abdomen 



oblong : Platyckirus, St. Farg. 

 Anterior tibiae never dilated ; abdomen 

 oval : Syrplius,, F. 

 Species black or greenish-black. 



Front rough or furrowed : Chrysogaster, 



Mg. 

 Front smooth : Chilosia, Mg. 



SyrpJms, F. This, the commonest genus, is repre- 

 ■sented by about thirty-five rather closely allied 

 species, all more or less resembling wasps. Abdo- 

 men bright yellow, with transverse black stripes ; 

 thorax yellowish, greyish, or livid ; legs thin, yellow 

 with black rings ; wings usually clear ; long about 



7-9 mm. The commonest species are S. rihesii, L., 

 corolla, F., pyrastri, L. ; larva figured by Westwood, 

 Class, Ins. ii. Fig. 130-21. Baltcatus, Deg., 

 Bouche has observed the metamorphoses of this 

 species, and liiniger, Mg. The larvae of this genus 

 feed on Apkidcc. 



Flatychirus, St. Farg., an allied genus of about 

 twelve British species, has a narrower abdomen, 

 several species being common ; about the length of, 

 and closely resembling Syrphiis. The venation in 

 SyrpJucs, Platyckirus, Chilosia, and Melanostoma is 

 very similar. Mr. Verrall, in the " Ent. Mon. Mag.," 

 gives some excellent notes on the British species 

 of Platychinis, 



Chilosia, Mg., a rather large genus of black flies, 

 more or less pubescent, rather stoutly built; wings 

 never marked, and generally grey or brown. Chiefly 

 found in woods and meadows, and most of the species 

 are more or less local ; long about 8-10 mm. A 

 continental authority (Professor F. Kowarz) has 

 recently revised the majority of the European species. 

 Rhingia rostrata, L., a characteristic species ; tawny 

 brown, with a black head and thorax ; tawny face 

 produced in the form of a strong, long, pointed 

 snout ; wings pale grey ; legs tawny ; proboscis long 

 and horny ; common ; long 7-8 mm. Reaumur found 

 the larva in cow-dung. 



Eristalis, Latr.— These are the typical "drone 

 flies," several species being very common, the larvre 

 living in stagnant water. 



E. ictiax, L., is a brown fly, with grey or pale 

 tawny marks on the abdomen ; face clothed with 

 short, pale yellow pubescence, with a strong, broad, 

 central black line ; legs brown, paler at the knees and 

 tips ; wings clear, or slightly brown at the base, fore- 

 border, and towards the tip ; thorax clothed with 

 short thick tawny brown pubescence ; abdomen very 

 variable in colour, sometimes entirely black ; very 

 common everywhere ; long 10-12 mm. 



I once placed a live cf in a glass-top box with a 

 dead 9 and it remained in cop. for about half an 

 hour. 



E. intricarius, L., abdomen thickly clothed with 

 black hair, tip with whitish hair ; base of the tibise 

 pale yellow ; wings clear ; scutellum surrounded by 

 thick yellow hair ; thorax clothed with black hair ; 

 rather smaller, less common, and more local than 

 tenax. The colour of the pubescence varies greatly, 

 being sometimes nearly all yellow, or with a reddish 

 tinge ; long 8-9 mm. 



E. arbusiorum, L., a very common species, smaller 

 than intricarius ; abdomen bare, tawny with, roughly 

 speaking, two black triangular spots on it, their 

 apices nearly touching ; legs black and yellow ; 

 wings clear ; thorax with greyish yellow pubesence ; 

 face with yellowish white hair ; frontal stripe in 2 

 black ; long 8 mm. ; very common everywhere ; 

 variable. 

 -.Volucella bombyla7is, L., a large bee-like fly covered 



