GYRINID.dE. 79 



DESCRIPTION. 



Body depressed, obovate ; underneath glossy, black, slightly bronzed ; upper-lip minutely punc- 

 tured ; front wrinkled between the eyes ; nose impressed on each side : prothorax anteriorly on each 

 side with a transverse series of punctures parallel with the margin, and with a slight discoidal trans- 

 verse impression; at the base obtusangular and somewhat wavy: elytra with nine very slightly 

 impressed furrows, the interstices of which are minutely punctured ; at the apex the elytra are 

 wavy ; epipleura black-bronzed : legs and anus testaceous. 



This species approaches very near to Gyrinus Americanus belonging to the same genus, of which 

 I at first regarded it as merely a variety, but upon comparing it with the specimen preserved in the 

 Linnean cabinet, it appears clearly distinct. That species is smaller, bronzed above, and the inter- 

 stices of the furrows are without punctures. 



XXXIX. Genus GYRINUS. Linn. 



(114) 1. * Gyrinus impressicollis. Channel-necked Gyrinus. 



G. (impressicollis) caeruleo-niger, nitidus; prolhorace anterius transverse profunde impresso ; elytris margine, et striarum punctulis, 



ceneo-nitentibus ; apice sparse punctatis obtusissimis. 

 Channel-necked Gyrinus, blue-black, glossy; prothorax anteriorly with a deep transverse impression ; margin of the elytra 



and punctures of their furrows glittering and bronzed ; apex very obtuse and irregularly punctured. 



Length of the body 4 lines. 



Taken in Canada by Dr. Bigsby. 



DESCRIPTION. 



Body glossy, black underneath, above blue-black. Head a little bronzed ; nose transversely 

 impressed, wrinkled ; frontal impressions large and deep : prothorax with a deep anterior transverse 

 impression, reaching nearly from side to side, in the centre of which is also a deep punctiform 

 impression, and behind it on each side two others, but wrinkled and more shallow ; on each side 

 also is a large gibbosity or boss : elytra nearly oblong, with eleven rows of shining bronzed punc- 

 tures ; at their apex the punctures are scattered, the margins also are bronzed ; epipleura black ; the 

 tip of the elytra is very obtuse and almost truncated : legs rufous. 



This species is very near G. marinus, but it is much larger, and is sufficiently distinguished from 

 it by the deep furrow or channel tbat runs quite across the prothorax, its more prominent bosses, 

 and its impressions. In G. marinus, also the punctures at the tip of the elytra are not scattered, 

 but mark out a crescent-shaped area, and the apex itself is not so obtuse. 



