74 Orthorrliapha brachycera, 



four black marginal bristles, Pleura greyish black, metapleura with 

 black hairs. Abdomen rather slender, deep velvet black, sometimes 

 slightly shining down the sides. Venter black or greyish black, shining. 

 Abdomen is somewhat sparingly clothed with short, black hairs; 

 venter simiiarly haired. Exterior genitalia very small and inconspicuous, 

 the lower lamellæ styliform, the upper broader. Penis is sometimes 

 seen betvveen the upper lamellæ as a very thin thread. Legs black 

 or brownish; the coxæ all dark, slightly greyish pruinose; hind meta- 

 tarsi slightly swollen. Femora short-haired, the hairs above a little 

 more conspicuous; front tibiæ with fine, slightly longish hairs below; 

 anterior tibiæ without bristles, hind tibiæ with small bristles dorsally; 

 front tarsi with fme hairs below as on the tibiæ, posterior tarsi 

 slightly spinulous beneath. Wings somewhat strongly brown fumi- 

 gated, darkest towards the anterior margin, irridescent. Veins brownish 

 or blackish, anal vein abbreviated ; discai cell lying before the middle. 

 Stigma brownish. Halteres black or blackish brown. 



Female. Eyes separated, frons not specially narrow, duU blackish. 

 Thorax black, very slightly shining, almost dull. Abdomen greyish 

 black, a little more shining. Legs as in the male, only the hind 

 metatarsi not thickened, and the fine hairs below the front legs ab- 

 sent. Wings nearly quite hyaline. 



Length 2,5 — 2,8 mm. 



This species is very like nigripennis, but it is with certainty distin- 

 guished by several characters; the male is distinguished by the thicker 

 hind metatarsi and a different shape of the exterior genitalia, the 

 wings are less blackish, more brown. The female has almost quite 

 clear wings, abdomen is black, not brownish, and thorax almost not 

 shining. In both sexes the legs are dark, and especially the front 

 coxæ show no trace of pale colour. Besides there are other more 

 minute characters, the dorsocentral bristles are longer, and also the 

 hairs on the venter are longer; the legs are less long, and finally the 

 species is smaller. 



Rh. umhrlpennis is rare in Denmark and has only been taken in 

 1908 on two localities; Tyvekrogen (the author), and at Nøddebo (J. 

 C. Nielsen); the dates are ^^/s and ^Vo; it seems thus in contrast to 

 nigripennis to be a spring species. It was taken in low herbage in 

 woods on humid ground or near water, among others it was sitting 

 in great numbers in the flowers of Taraxacum. 



Geographical distribution:— Europe down into Spain; it seems 

 to have its northern limit in Denmark, as there is every reason to 

 take Zetterstedt's nigripennis to be the preceding species. 



Remarks: It is beyond doubt that this and the preceding species 



