488 Syrphidae. 



knob and down to the mouth edge black and shining, and likewise 

 Ihe lower lateral parts; vertex with slight, yellow hairs and frons 

 vvith quite short and slight, likewise yellow hairs; epistoma nearly 

 quite bare, only with a few, white hairs at the eye-margins; the 

 epistoma is much hollowed below the antennæ with a central knob 

 as much protruding as the antennal proniinence, and below it a little 

 retreating, the lower part of epistoma thus somewhat protruding but 

 only slightly descending. Occiput black, greyish white pruinose on 

 the lower part but only slightly above ; the hairs white and longish 

 below, yellow and quite short above. Antennæ reddish yellow, the 

 basal joints darker to blackish, third joint short ovate; arista long, 

 thin. Thorax black or æneous black, shining, the front margin some- 

 what indefinitely whitish pruinose; thorax is clothed with quite short 

 hairs which are yellow or mixed black and yellow on the front half, 

 black and more dense on the posterior half, and the disc therefore 

 here more densely punctate as in Tropidia. Scutellum black, densely 

 punctate, with quite short hairs which are black or more or less 

 brownish yellow; at the margin are short, brownish yellow, bristly 

 hairs; the scutellum is distinctly marginate. Pleura with longish, 

 whitish hairs, a little yellow above. Abdomen black and yellow, marked 

 in a somewhat similar way as in Tropidia-, first segment greyish black 

 except the yellow sides, second segment yellow with black middle line, 

 generally a little widening forwards, broadest just before the front 

 margin; the third segment may be nearly quite yellow with a black 

 middle line, but it is generally more or less black on the hind part, 

 and sometimes only the basal corners are more or less reddish; fourth 

 segment æneous black; abdomen may thus be termed yellowish with 

 the base, a larger or smaller apical part and a broader or narrower 

 dorsal line black; it is dullish on the basal part, shining on fourth 

 and on the greater part of third segment, and it is clothed with short 

 hairs, which are pale on first segment, black on second and third but 

 yellow and slightly longer on fourth segment; at the sides they are 

 all yellow, and they are long at the basal corners; venter yellowish 

 with just the base and the fourth segment blackish, often also the 

 hind part of third segment dark; it has longish, pale or brownish 

 hairs. Legs black, shining, all tarsi with the three first joints yellow, 

 on the front tarsi generally somewhat darkened : all knees may some- 

 times be slightly and obscurely reddish; all femora somewhat thickened, 

 front and hind femora the most; anterior tibiæ a little thickened to- 

 wards the end; hind tibiæ a httle curved, somewhat thick about the 

 middle, and with a small elevation below just above the middle. The 



