TPtE CANADIAN ENTOMOLOGIST. 89 



adjoining the suture, and the two others being discoidal ; between the 

 outer one and the margin, especially near the apex, are some scattered 

 punctures; the epipleura, and sides of the tore-breast, are yellow: legs 

 testaceous ; thighs and t i V) I re punctured. 



This species is intermediate between C. sirjatus and C. dolabrahrs, 

 with the former it agrees in the majority of its characters, particularly in 

 the longitudinal rows of punctures, except that its sutural cue is mpre 

 perfect ; and with the latter in the prothoracic band and the color of the 

 legs. The transverse farrows of the elytra are rather deeper than those ct 

 the first-mentioned species, and not so deep as those of the last. 



These insects, adding C. fttsats, may perhaps be regarded as forming a 

 subgenus, whose common character is the peculiar sculpture of the elytra. 



[Synonymous with C. scitfptilis Harris ; a species taken in Canada.] 



10S. COLYMBETES (Hvdaticus) Rugtcollis, Kirby. — Length of 

 body 6 lines. Taken in Nova Scotia by Dr. MacCulloch. 



[74.] Body rather obovate and depressed; underneath rufous cloudy 

 with dusky. Head subrufous, dusky behind; antenna? and palpi yel- 

 lowish, dusky at the tip ; prothorax with the posterior angle acuminate, 

 subrufous, dusky in the disk, posteriorly scratched longitudinally as if by 

 a pin ; elytra pale-yellow, thickly and minutely reticulated or vermiculated 

 with black ; lateral margin yellow, unspotted ; epileura yellow ; prester- 

 num depressed. This species appears to represent C. H. irroraius. 



109. Colymbetes (Hydaticus) MacCullochii, Kirby. — Length of 

 body 5^4 lines. Several taken in Nova Scotia by Dr. MacCulloch. 



Body obovate, depressed, glossy ; underneath black, continently 

 punctured and wrinkled. Head posteriorly minutely punctured, black ; 

 nose, mouth, and its organs, and a band between the eyes pale yellow ; 

 antennae pale with the joints above dusky at the tip : prothorax punctured, 

 pale yellow, with a discoidal band, dilated at each extremity and sur- 

 rounded by a black margin of the same colour : elytra black, sprinkled 

 with innumerable pale-yellow dots ; near to the apex is a pale, angular, 

 undulated band, anel beycrld it a round white spot ; the margin of the 

 elytrum is paler than the rest : the three intermediate ventral segments 

 of the abdomen have each a pair of roundish pale spots, one en each side; 

 the four anterior legs are pale yellow. [Previously described as Acilius 

 Mediaius Say — Ent. Works ii. 508.] 



no. Dytiscus ooligeukii, Kirbx. — Length of body : male. 1 inch 



