136 DURHAM DIPTERA. 



XXIV. 223. 



323. Dolichopus, Ltr. 



1 (38). Femora all black. 



2 (9). Lower post-orbital bristles yellow. 



3 (8). Antennae all black. 



4 (5). Legs all black, except the extreme tip of the femora. 



Wings dusky. 



1 191. Dolichopus atripes, Mg. 

 Waskerley, 1 $, 1 $, July, 1901; Hesleden, 1 ?, 

 August, 1 90 1. 



5 (4). Fore tibiae pale. 



6 (7). Hind tibiae dark. Tarsi with only one bristle above. 



Wings dusky. (1192. phaopus, Hal.) 



7 (6). Hind tibiae only dark at the tip. Wings clear. 



1 193. Dolichopus vitripennis, Mg. 

 Waskerley, 7 $, 5-7-01. 



8 (3). Antennae with the first joint pale beneath. Hind 



femora with a pale fringe beneath. 



( 1 20.1. clavipes, Hal.) 



9 (2). Lower post-orbital bristles black. 



10 (18). Hind metatarsi very bristly. 



11 (12). Wings blackish on the outer half. 



1 1 94. Dolichopus atratus, Mg. 

 Waskerley, 3 $, 4 $, July, 1901 ; Bedburn, 1 $, July, 

 1901. 



12 (11). Wings all dusky, legs brownish, picipes, Mg. (1195). 



13 (10). Hind metatarsi not very bristly. 



14 (15). Legs entirely black except the pale knee joints. 



(1199. melanopus, Mg.) 



15 (14). Legs with more than the knee joints pale. 



16 (29). It is a male. (The males in this genus are easily 



distinguished from the females by the strongly 

 developed genitalia, bent under the abdomen). 



17 (24). Fifth tarsal joints of neither the fore nor mid legs 



enlarged. 



