260 GEO. H. HORN. 



Cvnibiodyta Bedel is said both by that author and Dr. Sharp to 

 have a laminate niesosternum, consequently this species is not refer- 

 able there, while neither author makes any mention of the toothed 

 claws, nor is there any reference to especially long maxillary palpi. 



For the above reasons I feel compelled to separate it, at least for 

 the present, with another generic name, the only other recourse being 

 to continue it with Cymbiodyta, in which it would certainly form a 

 well marked subdivision. 



H. bifi<lus Lee. — Oblong-oval, feebly narrowed in front, pieeous, shining, 

 subflepressed. Thorax closely and finely punctate, more coarsely and less closely 

 at the sides, the usual arcuate and transverse rows of coarser punctures well 

 marked, lateral marginal line deei)ly impressed, basal line wanting. Elytra 

 rather deeply striate, especially at the sides and near the apex, the strife all en- 

 tire, except the sutural and second, at bottom not punctate, intervals convex at 

 the sides, flatter on the disc, punctate, more coarsely and less closely than the 

 thorax, the sides of each interval slightly crenate, alternate intervals without 

 coarser punctures. Body beneath and eyes black, opaque, tarsi rufo-testaceous. 

 Length .22— .28 inch. ; 5.5—7 mm. 



Prosternum simple, niesosternum with a pyramidal process, higher than wide 

 at base, when viewed from behind in form of A. 



Claws dissimilar in the sexes and unlike on each pair of feet. 



In the male the anterior claw of the front feet has a rather broad 

 but acute triangular tooth, the posterior claw ratiier abruptly broader 

 at base, but not truly toothed ; the middle feet have anterior claws 

 toothed but in a less degree than the front feet ; the posterior claw 

 is as in the front feet ; the posterior feet have both claws alike, and 

 they are very nearly like the posterior claw of the middle feet. 



In the female the claws are merely broadened at base without 

 forming a tooth. 



This insect resembles, in form and sculpture, Hydrobins fusclpes, 

 but is less convex, and is usually found associated with that species 

 in series sent by collectors. Independently of the more important 

 structural characters, the long and slender maxillary pal])i will at 

 once distinguish it. 



Occurs in Canada and the Lake Superior region. New England 

 States southward to Georgia (coll. Lee). 

 



The species which were of old included in Hydrobius seem to 

 have o'iven much more trouble in their .separation into tenable genera 

 than Philydrus. The following table is the result of a study of the 

 described genera from the literature as far as they are represented in 

 our fauna; MetacymHS is included for discussion. 



