500 WESTWOOD ON THE 



Of a pale fuscous colour, with a distinct yellowish median line on the 

 prothorax : the head is yellowish, with two elongate fuscous spots, 

 which extend to the margin of the prothorax, in this respect differ- 

 ing from the common British species C. virescens of Pictet, to 

 which it is very closely related ; in C. virescens these spots are of 

 a nearly circular form : the wings are hyaline, very shining, and 

 tinged with yellow at the base, with scarcely any admixture of 

 green ; the nervures of the fore wings, and those of the apex 

 of the hind wings, are brown. 



Inhabits Canada, &c. Taken by Messrs. Doubleday and 

 Foster, at Trenton Falls. The difference between this and 

 the British cognate species, considered independently of tlie 

 widely-removed localities, is quite insufficient for the establish- 

 ment of a species. 



Genus. — Si alts, Latreille. 



Sialis infumatus. Nigray alis vix hyalinis, nigro-punctatis, basi 

 proecipue infuscatis. (Corp. long. "3 unc. ; alar, dilat. '8 

 unc.) 



This species differs principally from Sialis lutarius in the dark shade, 

 approaching to black at the base of the fore wings : the entire 

 body is black, including the antennae and legs, and the wings are 

 scarcely transparent, and thickly sprinkled with minute black dots. 



Inhabits North America. A single specimen taken by Mr. 

 Doubleday at Trenton Falls. 



Art. LI. — On the Genus Cerapterus of Swederus. 

 By J. O. Westwood, F.L.S. 



This extraordinary genus of Coleopterous insects was esta- 

 blished sixty years ago (1788) by Swederus, w^ho described a 

 single species, C latipes. To these Donovan added another 

 from New Holland, C. MacLeaii, and I described a third in 

 my Monograph on the Paussidce, under the name of C. Hors- 

 Jieldii ; without, however, being quite certain of its specific 

 difference from C. latipes. In the last part of the Transac- 

 tions of the Entomological Society, I figured an Australian 

 species from the collection of M. Gory, which, judging from 

 the acknowledged inaccuracy of Donovan in minute points 

 of organization, I regarded, but doubtingly, as identical with 



