Eristalis. 433 



pale brown, plumose on the basal two thirds. Thorax brownish black, 

 dull, the front half a little pale pruinose with two approximated middle 

 stripes and a large, roundish side spot darker; it is clothed with yellow 

 hairs. Scutellum yellow or brownish yellow, with yellow hairs, gene- 

 rally black on the middle. Pleura with long yellow hairs. Abdomen 

 somewhat elongate, narrowed backwards and thus conical ; it is black 

 or bluish black, dull, third segment with a shining, transverse middle 

 band and fourth segment quite shining or somewhat dull on the front 

 and hind part; there are two yellow, triangular side spots on second 

 segment, sometimes rather small, they are dull except just at the side 

 and behind; there are more or less distinet narrow, yellow hind margins, 

 most distinct on second segment. Abdomen is clothed with yellow 

 hairs, pale just at the base, the hind margins of third and fourth 

 segments more or less black-haired, and sometimes the hind margin 

 of second segment, a large hind part of third and almost the whole 

 fourth segment are black-haired, but at the sides the hairs are yellow. 

 Venter grey with pale incisures, the two basal segments often pale, 

 with grey middle spots ; the venter is clothed with long, yellow hairs. 

 Legs with the femora black with yellow apex, on hind femora very 

 narrow, front tibiæ with the basal half or two thirds yellow, middle 

 tibiæ quite yellow with only the apex more or less black and hind 

 tibiæ with about the basal half yellow ; anterior tarsi all yellow, hind 

 tarsi black, more or less pale towards the apex; hind tibiæ a little 

 compressed and curved, hind metatarsi slightly thickened. The legs 

 haired in the usual way, the hairs all yellow, only the fringes on the 

 apical part of hind tibiæ more or less to quite black and the bristly 

 hairs below apex of hind femora black, generally also some few black 

 hairs behind front femora towards the apex; the anterior, especially 

 the middle femora, with long fringes behind. Wings more or less 

 yellowish on the basal half towards the anterior margin, the colour 

 especially visible below the stigma, where it may form a faint cloud. 

 Stigma more than twice as long as broad, dark brown. Squamulæ 

 and fringes yellowish brown. Balteres yellow. 



Female. Vertex and frons broad, widening downwards; they are 

 almost quite black with only a yellow pruinose band somewhat above 

 the antennæ; the hairs almost all black or they are yellow across on 

 the yellow pruinose band. The antennal arista plumose nearer to the 

 apex than in the male. Abdominal spots about as in the male or a 

 little smaller. Wings less tinged. 



Length 11 — 15,5 mm. 



This species resembles E. tenax but cannot be confused with it. 



E. pertinax is common in Denmark ; at Copenhagen, Ordrup Mose, 



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