48 Syrphidae, 



Male. Vertex large and long, the eye-suture short; the vertex is 

 black, yellowish or brownish-haired ; the very small frons yellow. 

 Epistoma protruding, somewhat keel-shaped, with a slightly produced 

 central knob in the niiddle ; it is yellow with a black middle line and 

 the lower margin black, and it is yellow-haired. Occiput black, pruinose 

 downwards, with yellow hairs above, white hairs below. Antennæ 

 black, the third joint brownish, paler beneath at base, twice as long 

 as broad; arista short, scarcely as long as the third joint. Eyes with 



Fig. 7. Antenna of P. tibialis d", from the outside. X 90. 



short, whitish pubescence. Thorax black or æneous black, shining, 

 densely punctate, with yellowish hairs, slightly longer on scutellum, 

 Pleura with long, white hairs. Abdomen with the first segment not 

 quite short; it is black, shining, somewhat densely punctate; the hind 

 margins of the segments, especially of the first, are polished; the ab- 

 domen is clothed with short, yellow hairs, rather long at the base of 

 the side margin. Venter translucent in the basal part, black towards 

 the end, with fine, longish hairs; the fourth ventral segment with a 

 slightly excised or about straight hind margin. Not rarely abdomen 

 has some red colour on the third segment, more or less defmed as a 

 triangular spot, and the hind margin of the fifth segment pale. Legs 

 yellow, anterior femora black in about the basal half, hind femora to 

 near the apex; hind tibiæ with a black ring in the middle; sometimes 



Fig. 8. Wing of P. tibialis. 



the black colour on the femora a little less extended, and the hind 

 tibiæ with a very weak ring or quite yellow, and this is always the 

 case in the specimens with red colour on abdomen. The hind femora 



