Lasiophthicus. • 261 



often on Umbelliferæ ; the common pyrastri is sometimes present in 

 great numbers, thus it was, according to Curtis (Farm, Ins. 1857, 81) 

 on ^^h 1818, a very hot day, present in England in such swarms that 

 it covered the fishermen's boats; I have also found the larva on 

 Phragmites in very great numbers. The species has also been found 

 joining the vast swarms of Syrphi sometimes occurring. 



Of the genus 3 species are known from the palæarctic region, 

 two of which occur in Denmark. 



Tahle of Species. 



1. Abdominal lunules whitish, those on third and fourth seg- 

 ments with their outer end farther from the front margin 

 than the inner end; venter with large, rectangular, trans- 

 verse spots 1 . pyrastri. 



— Abdominal lunules yellow, those on third and fourth seg- 

 ments with the inner and outer end equally near the front 



margin ; venter with smaller, elongate middle spots 2. seleniticus. 



1. L. pyrastri L. 



1758. Linn. Syst. Nat. X, 594 et 1761. Fn. Suec. 1817 et 1767. Syst. 

 Nat. XII, 2, 987, 51 {Musca). - 1764. O. F. Mull. Fn. Fridrichsd. 721 

 {Musca). — 1775. Fabr. Syst. Entom. 771, 42 {Sijrphus) et 1805. Syst. 

 Antl. 249, 3 {Scaeva). — 1822. Meig. Syst. Beschr. 111, 303, 44 (Sijrphus). 



— 1843. Zett. Dipt. Scand. II, 703, 5 et 1859. XIII, 5091, 5 (Scaeva). — 

 1862. Schin. F. A. I, 301 (Syrphus). — 1901. Verr. Brit. FL VIII, 334, 1, 

 figs. 278—279 (Catabomba). — 1907. Kat. palåarkt. Dipt. III, 56. — Syrphus 

 transfugiis Fabr. (nec L.) 1794. Ent. Syst. IV, 306, 104 et 1805. Syst. Antl. 

 250, 5 {Scaeva). 



Male. The broad, inflated frons and the epistoma yellow; the 

 extreme mouth edge darkened, and the central knob with a narrow, 

 blackish line; the extreme hinder lower corner of epistoma black; 

 jowls grey. Vertex black-haired, frons with very dense, black hairs, 

 and epistoma black-haired down the sides and more or less about 

 the central knob, for the rest yellow-haired ; sometimes it is more 

 yellow-haired. Occiput grey pruinose, with yellow hairs, above a row 

 of black hairs, overhanging the eyes. Eyes densely hairy with longish, 

 brownish, downwards paler hairs. Antennæ blackish, with the basal 

 joints and the extreme lower base of the third joint reddish; some- 

 times the antennæ more brownish. Thorax bluish æneous, shining, 

 a little yellowish at the sides; it is clothed with long, but not dense, 

 yellow hairs, generally intermingled with some few black at the sides. 

 Scutellum brownish yellow, shining bluish, with long, black hairs and 

 at the base more or fewer yellow hairs. Pleura with longish, pale 



