Dolichopodidae. 313 



sack-like protruding; it and the oral aperture are of the same or 

 practically the same size in both sexes. Labrum (diadema) is rather 

 curious; it is broad and rounded in front, and wilhout any median 

 tooth, but on each side below there is a strong, black tooth; it is 

 thus almost divided into two as the middle part is slightly chitinised; 

 hypopharynx likewise of a curious shape; it is a little longer than 

 labrum, not very broad at the base, but very strong and strongly 

 chitinised ; it is curved downwards with the apex and this latter is 

 two-pointed, as there is a strong hook behind the apex on the lower 

 side; the maxillary palpi are irregularly oval, squamiform, not speci- 

 ally large, with hairs and bristles. Labium strong, and both basal 

 part and labella strongly chitinised ; the basal part is roundish quadratic, 

 with two short triangular processes behind ; the labella are large and 

 broad, soft on the inside, but here with radiating chitinous ridges; 

 when closed the labella form a compressed, somewhat wedge-shaped 

 piece, when spread out they are circular, enclosing a cylindric hole. 

 The mouth parts are provided with rather enormous muscles. Of 

 all Dolichopodids I have examined Medeterus has the most power- 

 ful mouth. Thorax rectangular, somewhat high, and arched above; 

 behind, in front of the scutellum, there is a flat or somewhat con- 

 cave area. Pro- and metathorax small, the former with small bristles 

 above. Acrostichal bristles distinctly biserial ; they are somewhat long, 

 or short to very short; the rows of dorsocentral bristles are generally 

 formed of more or fewer small bristles in front, and two to six longer 

 bristles behind, or only of long bristles in various number (3 — 6); 

 further there is a humeral bristle, and generally a weaker, a post- 

 humeral, two notopleural, the posterior generally small, three supra- 

 alar, the median generally small and in micaceus I found only two 

 supraalar, the median quite wanting; fmally one postalar bristle; 

 there is no præsutural bristle. Scutellum bare above, it has two or 

 four marginal bristles, in the latter case the median pair strongest. 

 The propleura have two to six bristles in a vertical row. Abdomen 

 somewhat short, more or less cylindrical, narrowed towards the end 

 and thus conical. In the male there are six dorsal segments of about 

 the same length, the first not being shorter; also on the ventral side 

 there are six distinctly chitinised segments of about the same length, 

 except the first, which forms a very narrow chitinisation; but the 

 ventral segments are folded somewhat up between the dorsal; the 

 seventh segment forms a somewhat long peduncle for the hypopygium, 

 it has both a chitinised tergite and sternite. The hypopygium is 

 smaller or larger, but generally rather large; it is pedunculated and 

 laid up under abdomen, its appendages often reaching to the base of 



