7. SARGUS 165 



rather dense pubescence all over the disc with much scarcer long thin hairs inter- 

 mixed, and these long hairs are from two to four times as long as the short dense 

 pubescence ; pleurae with longer pubescence, but the middle part of the mesopleuree 

 bare, polished, and depressed so as to admit the front femora. Scutellum unarmed, 

 and similar to the thorax iti colour and pubescence ; raetanotum large, conspicuous, 

 and polished, pubescent on its lower part. 



Abdomen rather club-shaped, quite twice as long as the thorax, brilliantly- 

 shining, and bearing obvious though not very conspicuous pubescence. Genitalia 

 small. 



Legs practically simple, rather long and thin ; basal joint of all tarsi, and especi- 

 ally the hindmost, long. Osten Sacken (Biol. Centr. Amer. Dipt., i., 24), speaks of 

 the tibiae of the male " showing the usual sexual characters,'' but I do not know 

 what they are. 



Wings long, with the normal venation of the subfamily ; costal vein extended 

 beyond the end of the cubital vein but not so far as the wing-tip ; pr^furca with the 

 discal cross-vein close to its base, and the radial vein subsequently diverging from the 

 cubital vein like a fork to the costa, so that the normal short fork of the cubital vein 

 looks like a second fork from the same vein, and this normal upper branch of the cubital 

 fork ends in the costa about half-way between the lower branch and the radial vein ; 

 discal cell emitting three long almost straight veinlets towards the wingmargin, ot 

 which the third does not extend to the margin, while the upper branch of the 

 postical vein only reaches the wingmargin faintly ; wing-membrane strongly ribbed. 

 Alar squamae moderately developed ; thoracal squamae of a very remarkable shape 

 being long narrow tongue-shaped, very pubescent, and placed close to the angle. 



This genus is easily distinguished from Chloromyia by its bare eyes, 

 and from Microchrysa by its much more elongate shape and the separated 

 eyes of the male. Loew formed a genus Chrysonotus, for S. hipimctatus 

 and some exotic allies, v^hich was supposed to be distinguished by the 

 equidistant ocelli, but I am unable to realise its generic distinction, 

 especially as I do not consider the ocelli of ;S^. hipunctatus to be absolutely 

 equidistant ; it is possible that a distinction might be found in the ocelli 

 being placed nearer the vertex in Chrysonotus than in JSargus, but I have 

 not been able to estimate that distinction as sufficient (figs. 136, 137). 

 I have made some remarks about the use of the word Chrysonotus under 

 the synonymy of the genus. 



Sargus is composed of a very uncertain number of European species, 

 as so many supposed species have been described from single specimens or 

 from insufficient material. Only four species can be considered well 

 recognised, although seventeen names appear in Kertesz's "Katalog," and 

 these four are not at all uncommon in Britain, while four or five other 

 unsatisfactory species occur with us. The metamorphoses of several 

 species are known, and Westwood (Introd. Mod. Classif. Ins., ii., p. 533) 

 says that he found many of the larvae of 8. cuprarius in garden mould, 

 though Leon Dufour records them from Elm {Ulmus) sores. Eeaumur 

 says that he found the larvse of a species which has been considered to be 

 ^S*. hipunctatus { = R6aumuri) in cow dung, and in confirmation of this 

 habit Colonel Yerbury has seen the females of >S'. fiavipes sitting on cow 

 dung while the males were on the leaves of shrubs near, which makes it 

 probable that Eeaumur may have had >S^. flavipes before him. The genus 

 is recorded from all Europe ; North, Central, and South America ; Asia, 

 even to its southern parts ; and South Africa. The flies often occur in 

 gardens, and are very quick in their movements during hot sunshine ; they 

 fly quickly about shrubs and settle upon the leaves but are very easily 

 alarmed. 



