DUEHAM DIPTERA. 49 



VI. 72. 



2 (13). Fore tarsi with long hairs in the male. 



8 (10). Dorsum with black or grey stripes. 



4 (7). Abdomen chiefly pale. 



5 (6). Large species, at least io mm. 



403. Chironomus plumosus, L. 

 A very common species. The females were abundant 

 over a farm pond at Hesleden, in August, 1900, 

 and the males were in a swarm cloud about a 

 hundred yards up a lane. 



6 (5). Smaller species, about 8 mm. 



(405. prasinus, Mg. ?) {intermedins, Staeg.) 



7 (4). Abdomen chiefly dark. 



8 (9). Ground of thorax grey. 



407. Chironomus annularis, Deg. 

 Harperley, 2 $, 26-5-99; Hesleden, 1 $, 16-8-00. 



9 (8). Ground of thorax yellow. (4*3- aprilinus, Mg.) 



10 (3). Dorsum with red stripes. 



11 (12). Large species, at least 10 mm. 



(404. ferrugineovittatus, Ztt.) 



12 (11). Small species, not over 6 mm. 



411. Chironomus flaveoius, Mg. (?) 

 Bishop Auckland, 1 ? , 20-7-00. 



. Fore tarsi bare in the male. 



. Ground of thorax grey. (409- riparius, Mg.) 



. Ground of thorax greenish-yellow. (416. tentans,¥.) 



27). Wings spotted, streaked, or clouded. 



, Halteres pale. 



, Legs not white ringed. 



, Abdomen dark. 



. Abdomen not banded. (4 1 !- scalenus, Schrk.) 



. Abdomen banded. (418. rufipes, L.) 



, Abdomen bright green. (4 I 9- flexilis, L.) 



. Legs white ringed. 



. Male fore tarsi with long hairs ; wings with only a 



small basal mark and one dark spot. 



(436. histrio, F.) 



D 



13 



(2). 



14 



(15). 



15 



(14). 



16 



(1)( 



17 



(26). 



18 



(28). 



19 



(22). 



20 



(21). 



21 



(20). 



22 



(19). 



23 



(18). 



24 



(25) 



