214 THE CANADIAN ENTOMOLOGIST. 



Cymbiodyta, Bedel. 

 Form very broadly oval ; serial punctures of elytra distinct at sides 



(.26-. 28 in.) rotunda^ Say. 



Form oval, serial punctures distinct (.18-. 22 in.) fimbriata., Mels. 



Form oblong, serial punctures wanting (.16-. 18 in.) laaistris, Lee. 



Helocombus, Horn. 

 Contains a rather large species {ff. bifidus^ Lee), .22-28 in. long, 

 resembling the vvell-known Hydrobhis fuscipes, L., from which it may be 

 separated by having the last joint of the maxillary palpi shorter than the 



preceding. 



Hydrobius, Leach. 



This name is now applied only to the larger species thereunder 

 included in the Check List, the small ones going into Creniphilus. They 

 separate thus : 



A. Brownish, elytra tessellate with darker (.28-. 30 m.)..tessellatus^ Ziegl. 

 AA. Black or piceous above. 



b. Form oblong, elytra striae distinct (.26-32 'm.)..fuscipes, Linn, 

 bb. Form short, very convex, elytra punctate in rows. 



Hind femora opaque and pubescent near base and along 



upper border (.30 in.) globosus, Say. 



Hind femora simply closely punctate near base, not pubes- 

 cent (.34 in.) tuviidus, Lee. 



Creniphilus, Mots. 



Smaller than the preceding, and usually found about pools. In 



form they differ among themselves, but are usually elliptical in outline 



and very convex. In the following table the name _/(?/;//««//.?, Lee. , is 



replaced by infuscatus, Mots.: 



A. Form oblong, fully twice as long as wide ; elytra narrowed behind, 



testaceous at sides (.c6-.o8 in.) suturalis, Lee. 



AA. Form elliptical, convex, not much longer than wide. 



(Colour above brownish to ochraceous (.08 -.10 



in.) in/uscattis, Mots. 



Colour above black or piceous, more or less bronzed. 



Presternum distinctly carinate (.06-.08 in.). subcupreus, Say. 



Prosternum simple (.10-. 14 in.) digestiis, Lee. 



Cercyon, Leach. 

 The species of this genus are mostly small ; black or piceous, as a 

 rule, and with more or less yellow on the tips of the elytra or sides of 



