306 Syrphidae. 



backwards is quite yellovv: the fourth segment has a yellow hind 

 margin and the fifth is quite yellow with a small, black middle spot. 

 The hairs on abdomen are somewhat short, they follow mainly the 

 ground colour but are somewhat pale at the base and between the 

 middle spots also when these are not united; at the sides the hairs 

 are long and yellow at the base, for the rest short and black. Venter 

 yellow, with black, transverse middle spots on the segments, which 

 spots vary in size and may be wanting on the hinder segments; it 

 has long, pale hairs, short and black on fourth segment. Genitalia 

 characteristic, they are large and swollen, sixth and seventh segments 

 reddish, eighth large, black and shining, ninth likewise unusually large, 

 reddish; the genitalia are pale-haired. Legs yellow with the basal 

 third of front femora and the hind femora except the apical part 

 black; anterior tarsi with the three middle joints brownish or the 

 front tarsi quite brownish; hind tarsi except metatarsus blackish. The 

 long hairs on femora yellow, more or less blackish outwards; on hind 

 femora there are but few hairs; the short hairs black on the anterior 

 side of hind femora and above hind tibiæ, for the rest yellow. Wings 

 slightly tinged. Squamulæ pale yellow with yellow margin and fringes. 

 Balteres pale yellow. 



Female. Vertex somewhat broad, black, the lower two thirds of the 

 frons yellow, above the antennæ may be a pair of dark spots; there 

 are small, yellowish side dust spots between which the black colour 

 may be slightly and vaguely produced; the hairs black. Abdomen 

 with the spots narrower or much narrower than in the male and 

 more lunulate; they are almost always separated, only in very rare 

 cases the third or second and third pairs may be narrowly united. 

 Legs paler, femora quite yellow, only the anterior black just at 

 the base. 



Length 7,5 — 10,5 mm, sometimes, but rarely, smaller specimens 

 are found, down to 6 mm. 



The larva and pupa are similar to those of nitens, likewise with 

 a clothing of very fine, dense spines, and they are of about the same 

 colour, the black markings forming longitudinal lines or rows of spots, 

 and there is a black middle line ; the pupa is 5 — 6 mm long. 



This species varies, as seen, much, especially in the male, but it 

 is, however, distinguished without difficulty ; in the male it is at once 

 distinguished by the characteristic large genitalia; in the female it is 

 distinguished from nitens by the yellow-haired scutellum and separated 

 abdominal lunules, and from latifasciatus by the presence of frontal 

 dust spots. — The varieties of the male have sometimes given rise 

 to confusion, and are no doubt often misunderstood, thus I got males 



