Empididae. 77 



of the „haustellum", and this character is, as well known, without 

 value, being dependent on the length to which the labium is extended ; 

 other characters mentioned are only such as are due to the degree 

 of maturity, 



22. Rh. gibba Fall. 



1815. Fall. Dipt. Suec. Empid. 32, 41 (Empis). — 1822. Meig. Syst. 

 Beschr. III, 58, 32. — 1842. Zett. Dipt. Scand. I, 437, 61 et 1849. VIII, 

 3045,61.— 1862. Schin. F. A. I, 101. — 1903. Kat.palaarkt.Dipt.il, 225. 



Male. Eyes not quite contiguous, leaving a very narrow frontal 

 stripe between them which is black, shining; epistoma somewhat 

 narrow, black. Occiput greyish black, only very slightly hairy. Labrum 

 about as long as the head is high, black, proboscis somewhat thick; 

 palpi blackish. Antennæ about of the length of the head, black, the 

 two basal joints short-hairy, the third joint somewhat elongated, the 

 style short. Thorax very much arched, black, strongly shining; the 

 disc is clothed with very short, black hairs; biserial acrostichal hairs 

 may be discerned, but the dorsocentral bristles are not distinguished' 

 from the other hairs towards the sides; only behind there are some 

 long dorsocentral bristles; of the usual bristles there seems only to 

 be one, a notopleural, present. Scutellum black, shining, with four 

 long, black marginal bristles. Pleura greyish black pruinose, meta- 

 pleura with black hairs. Abdomen short and robust, black, shining, 

 with short, black hairs; venter similarly coloured and haired. Exterior 

 genitalia somewhat thick, there is a large, arched plate below (eighth 

 ventral segment?), and a pair of upwards directed lamellæ above; 

 between the latter the penis extends as a thin, ferruginous thread, 

 curved upwards. Legs black or brownish black, shining; coxæ some- 

 what blackish grey pruinose; hind femora thick, the hind tibiæ of a 

 curious shape, curved, somewhat nodose, and hairy; hind metatarsi 

 slightly thickened. Front femora short-haired ; the middle femora 

 have a row of hairs below, and the hind femora are similarly haired ; 

 the front tibiæ have no bristles, the middle tibiæ have a pair of 

 bristles on the dorsal side, the hind tibiæ are short- and densely 

 haired on the dorsal side, the hairs stopping a little before the base, 

 and here forming a small tuft; tarsi short-haired. All the hairs 

 brownish. Wings whitish hyaline; veins white or yellowish, radial 

 vein short, discai cell elongated, the medial cross-vein quite near to 

 its base, anal vein not reaching the margin. Stigma narrow and 

 very faint, scarcely observable. Halteres black. 



Female. Eyes separated, frons narrow, shining black. Legs 

 simple, without bristles ; hind femora short ciliated below, hind tibiæ 



