60 Orthorrhapha brachycera. 



segments are paler. Venter grey, but often pale yellowish or brownish 

 to a higher degree than the dorsal side; abdornen is densely clotiied 

 with black or brownish hairs, somewhat long and erect at the sides; 

 the hairs at the hind margins are not stronger than the others ; venter 

 somewhat sparingly haired. The exterior genitalia are large and 

 curious, I interpret the structure in the following way: the sixth 

 ventral segment is turned downwards so that its hind margin points 

 down, the somewhat large seventh segment is turned in the same 



way, its downwards pointing hind margin 

 is arched, and its ventral side, which 

 points forwards, is black and shining; 

 the somewhat folded connecting mem- 

 brane between the seventh and eighth 

 ventral segment is distinctly seen; the 

 eighth ventral segment is very large, 

 Fi''. 18. Rh. pluniipes somewhat elongated, arched and with 



male genitalia. the sides and the hind margin curved 



upwards; it has somewhat long hairs at 

 the hind margin; the lower lamellæ are somewhat small, not stretch- 

 ing beyond the apex of the eighth ventral segment and somewhat 

 hidden in it; the upper lamellæ seem to be small and styliform, but 

 they are only indistinctly seen. Penis is hidden, only the upper, 

 thread-shaped end may sometimes be seen between the lamellæ. 

 Legs black or brownish, the knees more or less pale, which is most 

 distinct when the legs are black; coxæ greyish pruinose. The anterior 

 femora have some fine hairs below; the middle femora have an 

 antero- and postero-ventral row of longer hairs, and besides an antero- 

 dorsal row; the hind femora have a dorsal row of short hairs and on 

 the basal half very long dorsal hairs, on the ventral side they have 

 a very dense and short, pale pubescence which is not observable on 

 the middle femora. Front tibiæ short-haired and only with a single 

 subapical bristle; middle tibiæ with some bristles on the dorsal and 

 ventral side; hind tibiæ with not long hairs on the dorsal and ven- 

 tral side, and with some dorsal bristles. Tarsi short-haired. Besides 

 the legs have the ordinary but sparse clothing of short hairs. The 

 hairs and bristles black or brownish. Wings hyaline; veins more or 

 less pale yellowish to brownish, anal vein reaching the margin, weak 

 in the middle. Stigma a scarcely observable, yellowish shade. Halteres 

 whitish or yellow. 



Female. Frons broad, grey, with an impressed middle-line; the 

 hairs on thorax and abdornen slightly shorter than in the male, the 

 thoracic stripes slightly more distinct. The middle femora short pen- 



