194 [September, 



{thoracica and urbana) ; first thin vein comes off with a strong curve 

 at or beyond the fork, and runs straight to the margin. Anal 

 protuberance small and papilla-like. 



25 (26) Halter es black. 



S ? . Wings tinged with yollowish-brown, first thin vein deeply 

 curved at its origin ; legs blnckish-brovvn, knees, fore tibi* and tarsi 

 yellowish, hind tibite with three spines, namely, two on the outer side, 

 one above the middle, the other close to the tip, and the third in 

 the middle of the hind or upper-side. Taken only in the spring, 

 abundant under carrion. 2 — 3^ mm. — cur cine r vis, Beck. 



26 (25) Hal teres yelloio. 



27 (28) Thorax from red to blackish, postalar celli always red or reddish ; cosla 



thickened, especially in the female. 



$ $ . Wings yellowish-brown, with a darker cloud at the apex, 

 or without the cloud (v. claripennis) ; legs yellow, hind tibite with 

 four spines — a pair in the upper third, one in the middle of the hind 

 or upper margin, and the other close lo the lower end on the outer 

 side. 2\ — 5 mm, — thoracica, Mg. 



28 (27) Thorax entirely black ; costa not thickened. 



29 (30) Hind tibix with five or six spines. A long and slender species. 



S $ . Wings deeply tinged with yellowish-brown, first costal 

 division about as long as the second in the male, and shorter than it 

 in the female ; femora blackish-brown, tibiae from yellow to rust colour ; 

 spines of the hind tibise— three or four on the hind or upper-side, 

 and two on the outer side, one at or near the middle and the other 

 close to the lower end. Taken in tlie spring under carrion, but 

 always scarce. 3 — 4^ mm. — urbana, Mg. 



30 (29) Hind tibix with only tioo spines. A short and stout species. 



S $ . Wings clear, first costal division longer than the second in 

 both sexes ; legs yellowish-brown, fore legs entirely yellow, hind tibiae 

 with a spine at the upper third and another close to the lower end, 

 both on the outer side. Taken in the spring and early summer. 



2\ \\\\n.—fennica, Beck. 



31 (24) Second thick vein hare ; the apical spine on middle tibix very small and 



weak. 



In the species under this head the costa is moderately long, 

 reaching barely beyond the middle, and joined by the thick veins at 

 very narrow intervals, so that the first costal division is from two to 

 four times as long as the other two together; the first thin vein comes 

 off nearly straight some way behind the fork, and runs in a double 

 curve to the margin. Anal protuberance very long and finger-like. 

 Hind tibiae with a row of very fine bristles or hairs on the hind or 

 upper margin as is so common in the species under Group II. 



32 (35) Hind tibise with short, weak bristles instead of the characteristic long 



spines. 



