54 DURHAM DIPTERA. 



VI. 76. 



9 (10). Thorax with black stripes. (49 1. pusio, Mg.) 



10 (9). Thorax with brown or reddish stripes. 



11 (12) (13). Thorax flesh-coloured with brown stripes. 



(490. flabellatus, Mg.) 



12 (11) (13). Thorax pale yellowish green with red stripes. 



489. Tanytarsus tenuis, Mg. 

 Belburn, \$, 17-5-00. Bishop Auckland, 1 ?, 



19-5-°°; l ?> 3- IO -°°- 



13 (11) (12). Thorax testaceous with brown stripes, abdomen 



green. (493- debilis, Mg.) 



78. Metriocnemus, v.d. Wulp. 



497. Metriocnemus fuscipes, Mg. 



Bishop Auckland, 9 $ , 1 ? , March, 1903. 



79. Diamesa, Mg. 



1 (2) (9). V.5. forks beyond X.5., which rests on V.5. 



(500. obsairimanus, Mg.) 



2 (1) (9). V.5. forks a little before X.5., which rests onV.5.a. 



3 (4). The fourth tarsal joint twice as long as the fifth. 



(501. chiron, Hal.) 



4 (3). The fourth tarsal joint shorter than the fifth, and 



notched at the tip. 



5 (8). Antennae of female 8-jointed. 



6 (7). Thorax all blackish grey. (5° 2 - walthii, Mg.) 



7 (6). Thorax and scutellum reddish, with stripes. 



(503. amnion, Hal.) 



8 (5). Antennas of female 7-jointed. (504. tryphon, Hal.) 



9 (1) (2). V.5. forks at X.5. Antennas scantily haired in 



the male, and not forming a plume. 



(505. tonsa, Hal.) 



80. Tanypus, Mg. 



1 (11). Dark species. 



2 (8). V.5. forks beyond X.5., which rests on V.5. 



3 (4). Wings quite bare. (53 1 - nervosus, Mg.) 



4 (3). Wings hairy. 



5 (6) (7). Wings many spotted. (511. punctipenms, Mg.) 



