310 Syrphidae. 



Dipt. III, 65. — S. arcuatus et var. lapponicus 1901. Verr. Brit. Fl. VIII, 

 380, fig. 297. — S. arcuatus p. p. 1862. Schin. F. A. I, 305. 



Male. Frons yellow with a dark, bilunulate spot above the 

 antennæ; epistoma narrower than in luniger, yellow with a black 

 iniddle line reaching about to the antennæ, the mouth edge and lower 

 lateral corners blackish ; jowls bluish æneous. Vertex and frons black- 

 haired; epistoma yellow-haired with some black hairs above, at the 

 sides of the antennæ. Occiput greyish pruinose, the hairs yellow, 

 above a few black, overhanging hairs. Eyes bare. Antennæ brownish. 

 a little paler below; third joint oval, a little longer than the tvvo 

 basal together; arista as long as or a little longer than the antennæ. 

 Thorax dark æneous or somewhat bluish, shining, postalar calli slightly 

 brownish; thorax clothed with yellow hairs, densest at the sides. 

 Scutellum yellow, with blackish hairs on the disc. Pleura with long, 

 yellow hairs. Abdomen somewhat marginale, duU black, shining at 

 base and apex. It has three pairs of yellow lunules about as in 

 luniger and isolated from the side margins; the first pair transversely 

 oblong, not sloping forwards at the sides; fourth and fifth segments 

 with narrow, yellow hind margins. The hairs on abdomen follow the 

 ground colour, at the sides they are long and yellow at the base, for 

 the rest black. Venter yellowish, with large, black, transverse spots 

 on the segments; it has long, pale hairs, towards the apex they are 

 shorter and dark. Genitalia of medium size, black. Legs yellow, 

 anterior femora with the basal third black, hind femora except the 

 apex black or blackish; hind tibiæ with a faint, dark ring in the 

 middle; tarsi with the three middle joints blackish, hind metatarsus 

 brownish. The long hairs on femora mainly yellow, only towards 



Fig. 124. Wing of S. lapponicus d". 



apex some black; the short hairs dark on the anterior side of hind 

 femora and mostly dark on hind tibiæ, for the rest yellow. Wings 

 nearly hyaline; the cubital vein distinctly dipped down above the first 

 posterior cell. Squamulæ pale yellow with yellow margin and fringes. 

 Halteres yellow. 



