54 Orthorrhapha brachycera. 



thread. Legs black or blackish brown, somewhat shining; coxæ 

 greyish pruinose; hind legs somewhat elongated, hind tibiæ somewhat 

 dilated towards the apex, the hind metatarsi distinctly thickened, 

 especially towards the base; also the front metatarsi sHghtly thickened. 

 Front femora short-haired above and with an antero- and postero- 

 ventral row of short hairs; middle femora with ventral and antero- 

 and postero-ventral rows of somewhat longer hairs and with hairs 

 on the anterior side, especially on the basal part; hind femora rather 

 short-haired, only with longer hairs above and below towards the 

 base; posterior femora with a scarcely observable, dense, whitish 

 pubescence below, most distinct on the middle femora; front tibiæ 

 with a dense pubescence below, and somewhat long hairs on the 

 postero-dorsal side; middle tibiæ short-haired on the dorsal and ven- 

 tral side, and with a few long bristles dorsally; hind tibiæ short- 

 haired ventrally, and with a row of less dense hairs dorsally and 

 here also with a row of long bristles; front tarsi short-haired and 

 with somewhat longer, dense hairs on the postero-ventral side; 

 posterior tarsi short-haired with slightly longer hairs above, and 

 slightly spinulous beneath, hind metatarsi with a few dorsal bristles; 

 all hairs and bristles black or brownish black. Besides the legs have 

 the ordinary clothing of short hairs. Wings hyaline; veins brownish, 

 the apical part of the subscostal vein and the cubital vein blackish ; 

 anal vein very weak outwards, but discernible to the margin. Stigma 

 distinct, blackish. Halteres whitish. 



Female. Frons broad, black. The hairs on the thoracic disc 

 short. The anterior tibiæ slightly pennate on the dorsal side, posterior 

 femora pennate on both sides, the scaly hairs longest and broadest 

 on the ventral side, on the basal half of the dorsal side of the hind 

 femora only slightly scaly; the posterior tibiæ pennate on the dorsal 

 side, ciliated on the ventral side. Wing-veins somewhat stronger than 

 in the male. 



Length 3,8—4,5 mm. 



This species is distinguished by the black, shining colour, the 

 shape of the exterior genitalia in the male, and the way in which 

 the legs are pennate in the female. 



Rh. tarsata is somewhat common; Charlottenlund, Ordrup Mose, 

 Ørholm, Tyvekrogen, Nordskoven at Jægerspris; on Langeland at Lo- 

 hals; on Fænø, and in Jutland at Hald near Viborg. My dates are 

 ''/o — ^Vt. Stæger took it on Corylus, sitting on the underside of the 

 leaves; I took it in great numbers on ^^/c at Hald; towards the 

 evening the males were hovering in the air around tree-tops with 

 the legs pendulous, and they were seen resting on the underside of 



