DURHAM DIPTERA. 53 



VI. 74. 



16 (15). Abdomen testaceous with black central stripe. 



(483- pygmatus, Mg.) 



17 (14) (18). Thorax white with three brown stripes. 



(482. melaleucus, Mg.) 



18 (14) (17). Thorax, abdomen, and legs all yellow. 



(484. ictericus, Mg.) 



19 (1). Halteres black. 



20 (21). Large black species, at least 8 mm. 



470. Orthocladius niveipennis, Ztt. (do/ens, Wlk.) 



Gibside, 8 $, 1 2 , 19-4-98. They were flying over 

 the Lily Pond. 



21 (20). Small species, black, at most 4 mm. 



22 (23). Fore tarsi hairy in the male. (47 5. barbicornis, F.) 



23 (22). Fore tarsi bare in the male. 



24 (25). Dull black species. 



479. Orthocladius stercorarius, Deg. 

 Very common. The larvae live in dung. 



25 (24). Shining black species. (480. lucens, Ztt.) 



75. Camptocladius, v.d. Wulp. 



1 (2). Antenna? with white plumes. (486. byssinus, Schrk.) 



2 (1). Antennas with dark plumes. 



8 (4). Wings whitish, size 2 mm. (485. aterrimus, Mg.) 



4 (3). Wings darkish grey, size about 1 mm. 



(487. minimus, Mg.) 



76. Tanytarsus, v.d. Wulp. 



1 (4). Thorax black unstriped. 



2 (3). Abdomen bright green. (488. punctipes, W.) 



3 (2). Abdomen shining dark brown. 



495. Tanytarsus flavipes, Mg. 

 Gibside, 3 <?, 2 ?, 19-4-98; Hesleden, 4 <?, 29-5-99, 



4 (1). Thorax striped. 



5 (8). Legs dark brown. 



6 (7). Olive green species. (494- vermis, Mg.) 



7 (6). Black species, thorax grey with black stripes. 



(492. prcecox, Mg.) 



8 (5). Legs pale. 



