152 Syrphidae. 



between the knob and the mouth edge the epistoma is distinctly hol- 

 lowed, and it is somewhat descending; the lower part is somewhat 

 protruding and the anterior margin of the oral aperture with a deep 

 curve. Eye-margins moderately broad, slightly pruinose, with longish, 

 pale hairs. Occiput greyish pruinose, the colour stopping under the 

 eye; the hairs are white below, more yeliowish above, and here there 

 are besides long, blaclc hairs. Antennæ of medium size, third joint 



Fig. 75. Antenna of C. variabilis c5", from the inside. X 75. 



squarely roundish, not longer than broad; they are black, third joint 

 rarely more or less dark brownish; arista rather long, short-pubescent. 

 Thorax æneous black, finely punctate, clothed with a double pubes- 

 cence of longer, black and shorter hairs which are partly pale, especi- 

 ally in front, and sometimes almost all pale; there are distinct noto- 

 pleural, postalar and scutellar marginal bristles, the latter are numerous 

 but not strong; supraalar bristles short. Pleura with long, whitish 

 hairs, more or less black above and behind. Abdomen somewhat 

 long and rather parallel-sided; it is black or somewhat bluish black, 

 second and third segments almost quite dull, only the latter a little 

 shining on each side in the middle; fourth segment shining; the hairs 

 are longish and erect at the sides, and here pale yellow except at 

 the hind corners of third and fourth segments, where they are black; 

 they are also pale at the base on most of or on the whole second 

 segment, but they are black, shorter and somewhat depressed in the 

 middle, beginning at the hind margin of second segment, and on third 

 and fourth segments a large triangular space with the point forwards 

 and stretching over about the whole breadth behind is occupied of 

 the short, black hairs. Venter bluish black, shining, with pale hairs, 

 long on the two first segments, short on the two last. Genitalia pale- 

 haired. Legs black, sometimes the anterior tibiæ dark piceous on the 

 basal half; femora pale-haired, but the long hairs behind front femora 



