Dolichopodidae. 329 



Moscou, 11. — Hydrophorus aeneivittatus Macq. 1827. Soc. Se. Lille, 1827, 

 38, 2. — Medeterus aeneivittatus 1838. Meig. Syst. Beschr. VII, 156, 27. 

 — Musca rostrata Fabr. 1775. Syst. Ent. 783,53. — Dolichopus rostratus 

 1805. Fabr. Syst. Antl. 269, 15. — Hydrophorus rostratus 1823. Fall. 

 Dipt. Suec. Dol. 4,6. — 1843. Zett. Dipt. Scaiid. II, 449,9, et 1849. VIII, 

 3055, 9. — Medeterus rostratus 1824. Meig. Syst. Beschr. IV, 61, 3. 



Male. Vertex and frons brownish grey. Epistoma somewhat 

 bi'oad, metallic green or bluish, shining, especially below, a little 

 greyish pruinose just above the transverse ridge and below the 

 antennæ. Palpi black. Oceiput grey; the postocular bristies yel- 

 lowish, somewhat long and dense, the uppermost are small and 

 darker. Antennæ black, third joint a little longer than broad; the 

 arista subapical, long, more than thrice as long as the antennæ. 

 Thorax grey pruinose, dull; seen from behind the metallic green ground 

 colour is seen ; the disc has three brown or somewhat coppery stripes, 

 the median abbreviated behind, the lateral in front; the acrostichal 



Fig. 102. Antenna of M. diudema d". X 65. 



bristles very short; the dorsocentral rows consisting of two somewhat 

 short bristles in front, and two longer behind; the rows do not reach 

 much forwards; the hairs on the front part of the disc are very 

 small and partly pale. Scutellum with four bristles. Pleura some- 

 what greenish or æneous, pale grey pruinose; propleura with three 

 to five whitish prothoracic bristles. Abdomen green, æneous or more 

 coppery, densely clothed with short, pale yellow hairs, and with pale 

 hindmarginal bristles on the first segment. Venter greyish, with pale 

 hairs. Hypopygium somewhat large, black; the eighth segment greyish, 

 with pale hairs at the margin ; the ventral lobes somewhat long, 

 dilated and variously excised at the apex; the outer lamellæ shorter; 

 both pairs yellowish or brownish. Legs with the coxæ grey, femora 

 yellow, the front femora, or the front and hind, or all femora with 

 the basal part more or less brown or blackish brown; tibiæ and tarsi 

 yellow, the very apex of the tibiæ and the apex of the four first 

 tarsal joints dark, the last joint quite dark; sometimes the apex of 

 the tibiæ dark to a greater extent, and likewise the tarsi more 

 darkened on the apical part; hind metatarsus very short, about one 



