Chrysogaster. 121 



5. C. virescens Loew. 



1854. Loew, Neue Beitr. II, 17, 36. — 1862. Schin. F. A. I, 270. — 

 1901. Verr. Brit. Fl. VIII, 200, 4, fig. 208. - 1907. Kat. palåarkt. Dipt. 

 III, 21. 



Male. This species is very similar to chalyheata. Frons and 

 epistoma about as broad as in chalyheata^ of more greenish colour, 

 haired in the same way; frons a little less inflated, with a large 

 longitudinal impression; central knob small, but well defined and 

 more projecting and likewise the mouth edge, which projects equally 

 with the central knob. Antennæ as in chalyheata. Thorax æneous, 

 slightly shining, but a little less punctate and slightly more shining 

 than in chalyheata, clothed with longish, dark hairs. Scutellum slightly 

 marginale. Pleura æneous, shining, without pruinose spots, black 

 haired. Abdomen coloured as in chalyheata, the sides generally more 

 æneous green ; it is clothed with short, dark hairs on the middle, pale 

 at the sides and here longer towards the base; abdomen is thus in 

 the whole more pale-haired than in chalyheata; on the second seg- 

 ment are pale hairs, but they are quile short, or only a few are 

 slightly longer. Legs black, haired as usual. Wings with the apical 

 two thirds brownish on the anterior half; stigma light brownish; upper 

 marginal cross-vein a little more steep than in chalyheata, and the 

 two veinlets from the lower angles seem to be longer than usual, 

 Plumula brownish or yellowish brown. Squamulæ brownish with pale 

 fringe. Balteres with the knob brown. 



Female. Much like chalyheata. Frons of about the same breadth, 

 somewhat bluish, the middle space and the cross-furrows fainter, and 

 the latter not reaching the ocelli; epistoma less dusted, and the mouth 

 edge more projecting. Vertex and frons quite imperceptibly haired. 

 Thorax more bluish and a little brighter than in chalyheata, likewise 

 very inconspicuously haired; the præsutural depression without long 

 hairs. Pleura with short but somewhat distinct yellowish hairs. Ab- 

 domen dull bluish black on the middle, but the duU space smaller 

 than in chalyheata, the margin much broader, more brightly shining 

 and less punctate; abdomen also more sparingly haired. Wings less 

 or almost not darkened. Squamulæ paler to whitish. 



Length 6,7—8 mm. 



This species is very similar to chalijheata but may be distinguished 

 with certainty by the smaller but more projecting central knob in the 

 male; in both sexes by the not yellow wing-base, the marginale scu- 

 tellum, the second abdominal segment without long hairs or Ihese 

 only few, and the pleura without pruinose spots; finally it is more 

 shining, especially in the female. 



