DURHAM DIPTERA. 43 



IV. 65. 



3 (2). 0.1. very narrow, V.3. straight. (369. halterata,Mg.) 



4 (1). V.4.a. complete. 



6 (6). Thorax orange above. (358. flavicollis, Mg.) 



6 (5). Thorax all or nearly all black. 



6a (6b). V.4. diverging from V.3. far beyond X.4. 



(371. clavipes, L.) 

 6b (6a). V.4. diverging at X.4. 



7 (8). Scutellum with yellow border. (357. scutellata, Lw.) 



8 (7). Scutellum not yellow bordered. 



9 (10). Fork of V.4. very short, 0.4. b. a small equilateral 



triangle. Very small species, i-ii mm. 

 375. Scatopse brevicornis, Mg. 

 Hesleden, 1 $, August, 1900. 



10 (9). Fork of V.4. long. 



11 (12). V.4.a. with a small hang- vein. 3-3^ mm. Yellow 



spots on thorax and base of abdomen. 

 353. Scatopse no tat a, L. 

 Common, Bishop Auckland, 6 $, May, 1900 

 Hesleden, 1 $, August, 1900. The larvas were 

 abundant in the museum macerating tub in the 

 autumn of 1904. 



12 (11). V.4.a. without a hang- vein. Black species. 1^-2 mm. 



356. Scatopse pulicaria, Lw. 

 Bedburn, 1 $, 7-7-02. 



67. Dilophus, Mg. 

 Larvae found under moss and at the roots of grain, &c. 



1 (4). Legs entirely black. 



2 (3). Wings quite clear in both sexes, front veins black. 



Stigma absent in male. (378. albipennis, Mg.) 



3 (2). Wings clear in the male, tinged dark brown in the 



female, front veins brown. Stigma distinctly 

 present. 



377. Dilophus febrilis, L. 

 Common everywhere. Hesleden, Bishop Auckland, 

 Evenwood, Bollihope, Wearhead. 



