Dolichopodidae. 341 



oiis, from five to a greater number (about 12) and then not quite 

 constant in number; there is a humeral bristle and one or two 

 weaker, a posthumeral, two notopleural and a postalar bristle; these 

 bristles are constant; then there is as usual a præsutural bristle and 

 three or four supraalar bristles, but these aro generally small and 

 not quite constant; only the hindmost supraalar is longer. The small 

 hairs on the front part of the disc are not numerous, some of them 

 may sometimes be rather strong. Propleura have fine hairs above 

 and below, and one or several bristles below. Scutellum bare, with 

 four marginal bristles, in a single case {hisetus) with only two. Ab- 

 domen generally short, sometimes shorter than thorax; it is a little 

 flattened or more cylindrical or even a little compressed, especially 

 in the males, and often truncate behind. In the male there are five 

 dorsal segments of nearly the same length, the flrst not shorter or 

 even a little longer than the following; the flfth is narrow, triangular, 

 or sometimes broader and with an excision in the hind margin at 

 each side; sometimes the sixth segment may just be seen at the end; 

 the seventh segment is very small and quite hidden; on the ventral side 

 the flrst segment is short but distinct, the three next are normal, but 

 the fourth often arched downwards or folded in the middle line and 

 here somewhat cleft; the other ventral segments are folded in forming 

 the obliquely truncate end or cavity enclosing the hypopygium; this 

 latter is quite imbedded, only the end of it, the eighth segment, may 

 just be seen at the apex of abdomen, and generally the outer lamellæ 

 are protruding downwards. The hypopygium {halticus) is small, the 

 basal part somewhat roundish, but the sides of the cavity prolonged 

 into two long posterior lobes, the outer lamellæ are therefore inserted 

 quite dorsally, at the base; they are somewhat short, oval or roundish, 

 lancet-shaped and hairy; as in Medeterus they are not free, but 

 somewhat united in the middle. (This hypopygium answers in shape 

 to that of H. algens figured by Snodgrass in Proc. Californ. Acad. of 

 Se. III, 1904, PL XXXIII, fig. 2, only halticus has the basal part rela- 

 tively more developed). In situ the hypopygium lies imbedded at the 

 oblique end of abdomen, with the posterior lobes pointing forwards. 

 In the female there are five visible abdominal segments, the others 

 hidden ; the last terminales with an ovipositor with hairs at the end, 

 The abdomen is more or less thinly clothed with short hairs, and 

 there are no hindmarginal bristles; the eighth segment in the male 

 has fine hairs. There are distinct dot-like impressions at the sides of 

 the first to the fourth or fifth segments, those on the first generally 

 hidden by the metaepimera. The legs have the front coxæ a little 

 elongated, and the front legs are of raptorial construction ; they are 



