290 Syrphidae. 



described the present species was Zetterstedt in 1838, and he deter- 

 niined it with doubt as topiariiis Meig. Osten Sacken gave it then 

 in 1875 the name torvus. 



8. S. ribesii L. 



1758. Linn. Syst. Nat. X, 593 et 1761. Fn. Suec. 1816 et 1767. Syst. 

 Nat. XII, % 987, 50 {Mvsca). — 1764. O. F. Muil. Fn. Fridrichsd. 720 

 (Mwsca). — 1775. Fabr.Syst.Entom.770, 41 et 1805. Syst. Antl. 248, 1 {Scaeva). 

 — 1817. Fall. Dipt. Suec. Syrph. 40, 6 (Scaeva). — 1822. Meig. Syst. 

 Beschr. III, 306,49. — 1843. Zett. Dipt. Scand. Il, 707,8 et 1849. VIII, 

 3132, 8 et 1855. XII, 4656, 8 (Scaeva). — 1862. Schin. F. A. I, 310. — 

 1901. Verr. Brit. Fl. VIII, 366, 13, figs. 281, 291. — 1907. Kat. palåarkt. 

 Dipt. III, 69. 



This species is much like torvtis, but the eyes are practically bare. 

 Male. Frons with a black, tridentate lunule above Ihe antennæ, for 

 the rest yellow or sometimes soniewhat greyish pruinose. Jowls yel- 

 low. Eyes practically bare as there are only fevv short and scaltered, 

 .slightly visible hairs. Antennæ paler Ihan in torvus as the basal joints 

 are pale beneath and the third joint more extensively pale. Thorax 

 with the hairs a little shorter. Abdomen as in torvus. Legs less 

 black, anterior femora with scarcely or at most the basal third black 

 and hind femora with a little more than the basal half black; some- 

 times the hind femora more black; front metatarsi often more or less 

 pale, and middle tarsi more pale than in torvus; the ring on hind 

 tibiæ generally slight or wanting. The long hairs on femora yellow, 

 sometimes wilh some black intermingled; the short hairs on hind 

 femora on the apical third of the front side all black, and the more 

 bristly hairs below here likewise black; above just at the apex of 

 middle femora generally a few black hairs; on hind tibiæ the hairs 

 above and on the anterior side black. Wings almost hyaline or more 

 or less yellowish or pale brownish tinged, especially towards the 

 anterior margin. 



Female. Vertex black, frons yellowish pruinose, above the antennæ 

 a black lunule and from it a black, more or less defmite triangle 

 stretches backwards and unites with the black vertex. Abdominal 

 bands generally narrower than in the male. Legs yellow, femora only 

 black at the exlreme base, tarsi mainly as in the male. The short 

 hairs on the anterior side of hind femora black on about the apical 

 half or more, and the more bristly hairs below forming a somewhat 

 distinct row; all hairs above and on the anterior side of hind tibiæ 

 black and the antero-dorsal fringe distinct. 



Length. Rather varying, from 8,6 — 13 mm, but rarely below 

 10 mm. 



