Ghrysogaster. 113 



Tahle of Species. 



1. Antennæ black 2. 



— Antennæ reddish or reddish brown 3. 



2. Mouth edge in the male about equally protruding with the 

 central knob; thorax densely haired and venter longish- 



haired ; larger species 1 . Macquarti. 



— Mouth edge in the male more projecting than the central 

 knob; thorax thinly haired in the male, almost bare in 



the female; venter short-haired ; smaller species 2. viduata. 



3. Frons and epistoma somewhat narrow; wings blackish . . 3. solstitialis. 



— Frons and epistoma broad; wings not blackish 4. 



4. Wings yellow at base; pleura grey pruinose above front 

 coxæ and on hypopleura ; central knob in the male large 



but slightly projecting 4. chalyheata. 



— Wings not yellow at base; pleura withoul grey pruinose 



spots ; central knob in the male small but more projecting 5. virescens. 



1, C. Macquarti Loew. 



1843. Loew, Stett. ent. Zeitg. IV, 250. — 1862. Schin. F. A. I, 269. 



— 1901. Verr. Brit. FL VIII, 199. — 1907. Kat. palåarkt. Dipt. III, 19. — 

 Chr. viduata Macq. (nec Linn.) 1827. Soc. Se. Lille, 194, 8 et 1834. Sult. 

 å Buff. I, 562, 9. — 1843. Zett. Dipt. Scand. II, 818, 2 et 1855. XII, 4670, 2 

 et 1859. XIII, 6023, 2. 



Male. Vertex, frons and epistoma black, shining; frons puffed out, 

 with a more or less distinct longitudinal or dot-like impression. Epistoma 

 hollowed bclow the antennæ, with a not large central knob and an 

 about equally protruding mouth edge; it is a little greyish pruinose 

 across below the antennæ. Vertex and frons with long, black hairs, 

 epistoma with shorter, paler hairs on the side parts, darker hairs below, 

 Eye margins narrow but distinct. Occiput æneous black, a little pruinose, 

 with black hairs, downwards and on the jowls pale hairs. Antennæ 

 small, black, third joint roundish; second joint with a couple of longish, 

 pale or darker bristles below; arista much longer than the antennæ, 

 thickened just at the base. Thorax æneous black, fmely densely 

 punctate and densely clothed with somewhat long hairs, which are 

 yellowish brown, more or less mixed with black until being almost 

 quite blackish; they are longest at the margin of scutellum. On the 

 front of thorax are very slight traces of three stripes, often scarcely 

 to be seen. Pleura with a little longer, generally darker hairs. Abdomen 

 duU velvet black on the disc, æneous and shining at sides and apex; 

 it is clothed with quite short, yellowish hairs, longer at the sides and 

 here increasing in length towards the base. Venter æneous green, 

 shining, with longish, pale hairs. Genitalia forming a large knob. 

 Legs black, with short, yellowish hairs, only somewhat long on the 



