Syrphus. 315 



or a few black hairs above. Eves bare. Antennæ blackish, pale below ; 

 arista as long as the antennæ. Thorax æneous or dark brass-coloured, 

 shining ; it is clothed with yellow hairs, densest at the sides. Scutellum 

 yellowish brown, densely yellow-haired. Pleura with long, yellow 

 hairs. Abdomen not very ovate, often rather parallel-sided, black or 

 more brownish black, shining, a little dullish on second segment. It 

 has a pair of large, triangular basal spots, widely separated in the 

 middle, going widely over the side margin and here occupying about 

 the whole segment; the third segment has a hånd at the front margin, 

 emarginate in the middle behind or interrupted; it goes over the sides; 

 the band may sometimes be reduced to small lateral spots or it mav 

 be quite wanting; the rest of abdomen is black. The hairs on ab- 

 domen somewhat long, mainly yellow but more or less black at the 

 hind margins of the segments and at the apex; at the side margins 

 they are yellow and somewhat long, longest at the base. Venter 

 yellowish on the basal half, black on the apical half, with long, yellow 

 hairs. Genitalia somewhat large, black, with black and some pale 

 hairs. Legs yellow, base of femora black ranging from just the base 

 to about the basal third; hind tarsi black, the last or tw^o last joints 

 more or less yellowish, front metatarsi sometimes blackish at the ex- 

 treme base. The hairs on the legs all yellow, or some few black 

 above the hind tibiæ. Wings a little tinged. Squamulæ yellowish 

 with a darker margin and fringe. Halteres yellow or pale yellow. 



Female. Vertex of medium breadth, black ; frons with large, 

 yellowish side dust spots, between which a black middle stripe down 

 to the black lunule above the antennæ ; the hairs black. Jowls yellow. 

 The basal abdominal spots larger than in the male, going near to 

 each other in the middle or united to a band ; the second band 

 generally un interrupted, and there is not rarely a narrow band at the 

 front margin of also the fourth segment (this band may also be present 

 in the male. but I have never seen it in any Danish specimen of this 

 sex). Legs with 'the femora not black at the base. 



Length 9,5 — 11,5 mm. 



As seen from the description this species varies a good deal with 

 regard to the abdominal markings, but in spite of this it is so 

 characteristic that it cannot be confounded with any other species. — 

 The type to the species, a male, is present in the collection of Tonder 

 Lund, and I have examined it. 



S. bifasciatus is somewhat common in Denmark; Copenhagen in 

 gardens, Ordrup Mose, Ermelund, Lyngby, at Sorø ; on Falster and 

 on Lolland at Maribo and Strandby; on Langeland at Lohals; in Jut- 

 land at Horsens. My dates are ^/r. — Vt, it is thus a somewhat early 



