DURHAM DIPTERA. 313 



XXXVI. 510. 



10 (9). Stigma rather long ; upperside of hind femora with 



three bristles near the tip. (pallescens, Mg.) 



11 (8). Hind femora without the black spot at the tip. 



(ex cis a, Lw.) 



12 (7). Abdomen only red at the end. (e?narginata, Lw.) 



511. Blepharoptera, Lw. 



1 (4). Sterno-pleurae covered with a fine pubescence in 



addition to the usual hairs. 



2 (3). Third antennal joint red. (2271. speetabllls, hw.) 



3 (2). Third antennal joint dark brown. (caesia, Mg.) 



4 (1). Sterno-pleurae with only the usual hairs, no fine 



pubescence. 



5 (8). More than one mouth bristle on each side. 



6 (7). Thorax and abdomen dark grey. 



(2277. modes fa, Mg.) 



7 (6). Thorax grey ; abdomen reddish. 



2276. Blepharoptera' serrafa, L. 

 Common. Bishop Auckland, 12 $ and 3 $, March- 

 July. 



8 (5). Only one mouth bristle on each side. 



9 (12). Sterno-pleurae with more than one strong bristle. 



10 (11). Back of the head and dorsum somewhat shining. 



{bis eta, Lw.) 



11 (10). Back of the head and dorsum entirely dull. 



Blepharoptera iners, Mg. 

 Hesleden, 2 ?, August, 1899; Harperley, 2 ?, April, 

 1900. 



12 (9). Sterno-pleurae with only one strong bristle. 



13 (14). Costal spines exceedingly short. 



(227 4. flavicornis, Lw.) 



14 (13). Costal spines long. 



15 (16). Thorax and abdomen entirely yellow. 



(2275. ruficornis, Mg.) 



16 (15). Body not wholly yellow. 



17 (20). Pleurae yellow. 



18 (19). Costa thickly spined. ( 22 73- inscripta, Mg.) 



