300 DURHAM DIPTERA. 



XXXIV. 489. 



7 (8). Blue-grey dusted species with distinct middle stripes 



on the dorsum ; frons entirely orange ; femora 

 strongly bristled. (nigriventris, Lw., $) 



8 (7). Yellow-grey to grey dusted species, with indistinct 



middle stripes; frons yellow in front, blackish 

 behind ; femora weakly bristled. 



(Jongicornis, Rossi., ?) 



9 (2). Dorsum and scutellum entirely matt-dusted, without 



shining middle stripes. 



10 (13). Fore femora with a black stripe on the upper side. 



11 (12). Arista thick to the middle, and gradually thinning; 



frons all orange, or shading into the dark vertex ; 

 large species. {flavipes, Fin.) 



12 (11). Only the first third of the arista thick, then suddenly 



thinning; frons nearly black, with a sharply 

 bounded red spot in front; small species. 



{minuta, Beck., $) 



13 (10). Fore femora without a dark stripe. 



14 (15). Frons black, much protruding, with only a narrow 



orange stripe over the antennae. 



{articulata, Beck., $) 



15 (14). Frons yellow, little protruding, only darkened on the 



vertex. (leucostoma, Ztt.) 



16 (1). Legs with at least the femora black. 



17 (18). Third antennal joint almost rectangularly cut short, 



under corner not rounded, upper corner not sharp. 



(nigripes, Ztt.) 



18 (17). Front of the third antennal joint with a sharp upper 



and a rounded under corner. 



19 (26). All femora, or at least the hind femora, with the 



extreme base orange. 



20 (23). Fore femora on the inner side with stiff bristles, 



which point forward. 



21 (22). Fore femora on the inner side with a tuft of from 



15-24 bristles. (2208. fasciata, Mg.) 



22 (21). Fore femora inner side with only 4-5 bristles. 



(cinerella, Ztt.) 



