44 DURHAM DIPTERA. 



IV. 67. 



4 (1). Legs partly yellow. 



5 (6). Dorsum entirely black. 



Dilophus femoratus, Mg. 

 Bishop Auckland, i ?; Evenwood, i ? , June, 1897. 

 This is new to the British list. 



6 (5). Dorsum black with yellow shoulders. 



379. Dilophus humeralis, Mg. 

 Howick, Northumberland, 1 ?, August, 1905. 



68. Bibio, Geoff. 

 Larvae live in earth, dung, and rotting vegetable matter. 



1 (6). V.3 1 much, or at least distinctly longer than X.4. 



(IV. 7.) 



2 (3). Legs black with orange femora. 



380. Bibio pomoncB, F. 

 Shull, 2 $, September, 1900 ; Wearhead, 3 £, 

 August, 1 90 1 ; Harperley, 1 $, July, 1900. I 

 have also picked it up on the coast washed up 

 by the waves. 



3 (2). Legs entirely black. 



4 (5). Thorax and abdomen entirely black, and black-haired 



throughout. 



381. Bibio marci, L. 

 Common, especially along the willow-bordered banks 

 of streams. 



5 (4). Dorsum and abdomen orange, or, if black, then the 



pleurae and abdomen pale-haired. 



(383. hortulanus, L.) 



6 (1). V.3 1 shorter, or at most as long as X.4. 



7 (18). Stigma prominent and sharply bounded. 



8 (13). Veins of the hind region almost as thick and dark as 



those of the front. 



9 (10). Hind metatarsus thin, and at least twice as long as 



the second tarsal joint. (386. venosus, Mg.) 



10 (9). Hind metatarsus somewhat swollen, and never much 

 longer than the next joint. 



