58 DIPTEEA. 



segment of the abdomen light yellow, with a narrow . 

 black stripe not quite reaching the hind margin . . albifrons, Wiedem. ($). U V 

 The whole anterior part of the thorax ashy; second 

 abdominal segment with a broader interval between 

 the side-spots tricolor, Jaenn. 



14. The yellow side-spots of the second abdominal segment 



approximate or contiguons anteriorly ; the ashy 



thoracic band interrupted or subinterrupted ; hind i , $ 



femora only moderately incrassate Sp. (no. 14) . , t& ^ AA* G^^&u^ 



The yellow spots of the second segment not approximate 

 in front j the ashy sutural band entire ; hind femora 

 considerably thickened fasciatus, Wiedem. 



15. Mesonotum with a shiuing, steel-blue band in front of 



the scutellum j eyes pilose at the top only .... scutellaris, Fabr. 

 Mesonotum with an ashy band in front of the scutellum . 16. 



16. Grey clouds in the marginal and submarginal cells . . 17. 

 Marginal and submarginal cells pure hyaline; smaller 



species 18. 



17. Pile of frontal triangle, and the front below, light yellow j 



hind tibise compressed and ciliate vinetorum, Fabr. 



Pile of frontal triangle and front chiefly black .... cemulus, sp. n. 



18. Very small species (6-7 millim.) ; hind femora consider- 



ably thickened ; spots of the second abdominal segment 



broadly separated minutalis, sp. n. 



Moderate-sized species ; hind femora moderately thick- 

 ened 19. 



19. Frontal triangle and front below white-pilose .... 20. 

 Frontal triangle and front below largely black-pilose . . 21. 



20. Second and third abdominal segments yellow and red, or 



with the middle brownish . . rufiventris, Macq. 



Second segment with a median stripe, and the rest of the 

 abdomen (except sometimes the narrow anterior angles 



of the third segment), black albifrons, Wiedem. ( ? ). wv 



21. Third and fourth abdominal segraents opaque, with a 



complete shining band Sp. (no. 18). 



Third and fourth abdominal segments more or less yellow 



or red Sp. (no. 21). 



l. Eristalis persa, sp. n., $ . 



AUied to E. circe. Pace shining black, thinly yellowish-dnsted on the sides, and with abundant, long, yellowish- 

 white pile. Front opaque brownish, with long and abnndant black and yellowish pile. Eyes long and 

 abundantly light-pilose. First two joints of the antennaj reddish-yellow (third joint wanting). Mesonotum 

 opaque brownish-grey in front, more blackish behind ; pile moderately abundant, in front light yellowish, 

 behind black. Scutellum shining black, with abundant black pile. Pleura? shining black ; pilo chiefly 

 black. Abdomen deep black, with moderately abundant black pile ; second segment opaque velvety, with 

 an interrupted shining cross-band, the spots wider on the margin ; third segment shining, with a bisinuate 



