298 Syrphidae. 



segments; they are deeply emarginated in the middle behind and they 

 slope forwards at the sides, going narrowly over the margin at the 

 basal corners, they thus form two semicircuiar spots connected in the 

 middle; the hind margin of the fourth segment is broadly yellovv and 

 the whole fifth segment is yellow so that the apex is quite yellow. 

 The hairs follow mainly the ground colour but are somewhat pale at 

 the base, and black at the apex ; at the sides they are yellow at the 

 base, for the rest alternating black and yellow according to the bands. 

 Venter pale yellow with dark bands at the hind margins of the seg- 

 ments, on the second segment divided into triangular side spots ; it is 

 clothed with long, pale hairs, more or less blaek on the dark parts. 

 Genitalia small, yellow, only eighth segment a little darkened behind; 

 they are yellow-haired. Legs yellow, middle coxæ greyish black, 

 anterior tarsi with third and fourth joints a little brownish, hind tarsi 

 blackish brown ; all the hairs are yellow except the short hairs on the 

 anterior and ventral side of the apical half of hind femora and on 

 nearly all the hind tibiæ, where they are black. Wings brownish 

 tinged. Squamulæ and fringes yellow. Halteres yellow. 



Female. I do not know the female; according to the descriptions 

 the vertex is black, frons pale yollow, the black colour of vertex 

 slightly produced in the middle. Vertex with black, frons with yellow 

 hairs. Abdominal bands going more widely over the side margin than 

 in the male. 



Length 10,5 mm. 



This beautiful species somewhat resembles a bright ribesii, but it 

 is narrower and easily distinguished by the black antennæ, yellow 

 and yellow-haired frons and quite yellow legs. 



S. diaphanns is very rare in Denmark, we have only one speci- 

 men, a male, taken on Funen between Odense and Middelfart (H. J. 

 Hansen); no date is given. 



Geographical distribution:— Northern and middle Europe, and 

 recorded down to Italy; towards the north to middle Sweden but 

 everywhere a rare species. 



14. S. nitidicollis Meig. 



1822. Meig. Syst. Beschr. 111,308,51. - 1843. Zett. Dipt. Scand. II, 

 709, 10 et 1849. VIII, 3133, 10 et 1859. XIII, 5092, 10 {Scaeva). — 1862. 

 Sehin. F. A. I, 310. — 1901. Verr. Brit. Fl. VIII, 375, 16, figs. 293—294. 

 — 1907. Kat. palåarkt. Dipt. III, 68. — Scaeva ribesii p. p. 1817. Fall. 

 Dipt. Suec. Syrph. 40. 



Male. Vertex somewhat narrow and elongate, longer than the 

 eye-suture, blackish; frons yellow, the upper half greyish pruinose the 



