DURHAM DIPTEBA. 279 



XXXIII. 474. 



8 (11). Abdomen partly translucent yellow. 



9 (10). Hind tibiae remarkably bristly. (prnata, Mg.) 



10 (9). Hind tibiae with the usual bristles. 



(2138. firetiosa, Schin.) 



11 (8). Abdomen nowhere translucent yellow. 



12 (13). Thorax black; abdomen with a rather distinct central 



stripe. ( 2I 39- fiallitibia, Rnd.) 



13 (12). Thorax and abdomen uniform light grey, the latter 



usually unmarked. (grisea, Stein) 



14 (1). Legs all black, at most the knees more or less yellow. 



15 (22). Mid coxae with a thorn. 



16 (19). Fore tibiae towards the end with a remarkable tuft of 



bristles. 



17 (18). Mid tibiae, inner side, second half suddenly enlarged, 



forming a thick tubercle. 



2140. Homalomyia ma?iicala, Mg. 

 Bishop Auckland, 2 $, May, 1900, April, 1902. 

 This species was breeding abundantly in the museum 



macerating tub along with Scatopse notata and 



another species of Homalomyia in the autumn of 



1904. 



18 (17). Mid tibiae becoming gradually thicker. 



(2 141. month's, Hal.) 



19 (16). Fore tibiae without unusual bristles. 



20 (21). Whole length of the hind tibiae remarkably shaggily 



haired. {ciliata, Stein) 



21 (20). Hind tibiae not remarkably hairy. 



2142. Homalomyia scalaris, F. 

 Common. Bishop Auckland, 8 $, May-October. 



22 (15). Mid coxae without a thorn. 



23 (24). Abdomen shining black, unmarked ; pubescence on 



the inner side of the mid tibiae very thin and 

 indistinct. (slroblii, Stein) 



24 (23). Abdomen otherwise coloured, or if shining black then 



the pubescence on the inner side of the mid tibiae 

 distinct and thick. 



