4. ATRICHOPS 291 



beneath the front tarsi I should not be surprised to learn that it is a 

 biting fly. It is recorded from nearly all Europe except the extreme 

 north. Mr G-. C. Bignell. bred a female on July 4, 1888, from a " water 

 moss." 



4. ATRICHOPS. 



Atrichops no v. gen. 



Frons of the male (practically) and the side-cheeks in both 

 sexes bare ; third joint of the antennae reniform. Abdomen 

 not conical. Anal cell closed. 



This genus is formed for the species which has been usually known as Atherix 

 crassipes Meigen. 



Head (fig. 193) more rounded and less tilted than in Atherix ; side-cheeks bare ; 

 frons of the male practically bare, of the female slightly narrowing from the vertex 

 to the antennae ; palpi slightly drooping, and hardly more than half the length of 

 the proboscis. Antennae reniform as in Atherix. 



Thorax not densely pubescent, but bearing only depressed moderately sparse 

 pale pubescence ; metapleurte as in Leptis with not very conspicuous pubescence. 

 Metanotum small and rather concealed beneath the scutellum, and with the side- 

 humps bare. 



Abdomen oblong, not at all conical, narrower than the thorax and with almost 

 parallel sides, banded dorsally but not spotted. Genitalia of the male large and 

 somewhat separated from the abdomen. 



Legs long; the anterior pairs thin, but hind pair rather dilated on femora, 

 tibial, and tarsi; front pulvilli and claws of the male distorted as in ^^/ier^a,-, but 

 the posterior claws unusually short; front coxte with less pubescence than in 

 Atherix ; "touch-hairs" beneath the front tarsi obvious. 



Wings (fig. 194) with a venation almost as in Atherix, but the cubital fork 

 long and rather narrow beginning nan^owly and ending with a veiy slightly bell- 

 mouthed opening ; cross-veins placed rather nearer the base of the discal cell (at 

 about one-quarter from the base) ; anal cell closed. The wings have a faint clouding 

 about the middle and round the outer margin, but no conspicuous markings as in 

 Atherix. Squamiae (alar) with a thin margin on which is a sparse but not short 

 single-rowed fi'inge. 



Atricho2)s (« Opl^ wx/^) is easily distinguished from Atherix by its figure 

 and by the bare side-cheeks. 



1. A. crassipes Meigen. A rather 

 small fly. Wings slightly clouded, and 

 the stigma conspicuously blackish. 

 Hind tibiae moderately, and hind tarsi 

 considerably, dilated. 



Rather like a Rhyphus. 



S . Head (fig. ] 93) about as wide as the 

 thorax and about one and a half 

 times broader than long, rounded off 

 behind because the eyes curve round 

 and even bend in a little to the ver- 

 tex. Frons and face entirely covered 

 with light grey dust, but otherwise 

 quite bare all over including the Fig. i^z.— Atrichops crassiiKs j. x 20. 



rather broad eyemargins and the 



front part of the jowls, except for two inconspicuous hairs on the upper 

 part of the frontal triangle ; frons and face forming a triangle ; the 

 sunken middle part of the face not small, and extending across under the 



