Dolichopodidae. 273 



prolongation is visible only on the inside, in otliers it is visible both 

 on the inside and also in a peculiar way on the outside above, and 

 the third joint is then deeply incised in the base; the construction is 

 in some respects as in Dolichopus, but the real shape of the second 

 joint is rather intricate and not easily understood ; when the pro- 

 longation is visible on both sides, it is somewhat canaliculated above, 

 and the upper basal lobe of the third joint fits into this groove. The 

 prolongation is of a carious shape ; it is in reality on the inside formed 

 partly from the prolonged basal part of the joint, partly from the 

 same coUar-shaped prolongation, which was mentioned under Doli- 

 chopiis, while on the outer side it is exclusively formed of this latter; 

 the position of the bristles indicates the border between these tvvo 

 parts; the mentioned prolongation is thus here not hidden in the 

 interior of the third joint, but lies free in a canaliculation on the 

 inside of the joint, the canaliculation going in some species through 

 the joint, forming a deep incision, and the second joint does not 

 overlap the third in the usual way. The arista is apical or, on account 

 of the apex being obliquely cut, a little subapical (in tarsatus it is really 

 dorsal); it is in the male shorter than or about as long as the an- 

 tenna, in the female longer; its first joint is short or somewliat shorts 

 The basal joint of the antennæ is either bare above or it has a single 

 hair or is more hairy; the second joint has bristles at the apical mar- 

 gin, the third joint is distinctly hairy all over and the arista is short- 

 pubescent. The proboscis, palpi and oi-al aperture are larger in the 

 female than in the male, but the proboscis is only slightly protruding 

 in both sexes. Thorax as in Porphyrops ; acrostichal bristles short, 

 either uniserial or more or less irregularly biserial, especially behind; 

 there are six dorsocentral bristles, the flrst placed quite in front (the 

 fourth of the bristles is generally a little smaller than the others, and 

 in some species it may be quite wanting); further there is a humeral 

 bristle, and besides a smaller hair or bristle, a posthumeral, tv^o 

 notopleural, a præsutural, three supraalar and a postalar bristle. Scu- 

 tellum with two strong marginal hristles, and a small or very small 

 hair at each side; sometimes it has more hairs at the margin; it is 

 bare above, or sometimes with some few hairs. Propleura with hairs, 

 longest below; the pteropleura are a little hairy below, and the 



1 Zetterstedt and even Mik. say (Dipt. Unlers. Jahresb. d. k. k. akad. Gymn. Wien, 

 187S, 13, Fig. 1 — 3) about the arista in the male of IS. rufipes that it is not 

 two-jointed and not articulated to the third joint (Zetterstedt however says: 

 "quasi in unum cum illo coalita"), but this is erroneous; under the microscope 

 the first joint of the arista and its articulation to the third joint are distinctly 

 seen, even in a dried specimen. 



18 



