NORTH AMERICAN COLEOPTERA. 245 



The only specimen before me is a male in not good condition, 

 enough remains to show that on the front feet the claws are dilated 

 at base, but not formincr a distinct tooth, the middle claws less dilated, 

 the posterior very feebly. 



It is hardly to be wondei'ed at that this species should have been 

 referred to Hydrobius, considering its rather small size, and that the 

 last two joints of the palpi are of about equal length, although the 

 presence of a mesosternal lamina in place of a protuberance should 

 have been suggestive. 



In the light of our present knowledge of the value of the form of 

 the pseudo-basal joint of the maxillary palpus and the presence of 

 the coarser series of punctures on the head, thorax and elytra, the 

 true position of the species becomes evident. 



Although smaller, the species is cU)sely related to carinatus, differ- 

 ing from that in the absence of any prosternal carina. This, how- 

 ever, seems rather a variable structure, so that future collections may 

 show this to be merely a variation. 



Occurs in the mountain regions of California near Lake Tahoe. 



P. uebulosiis Say. — Oval, .slightly oblong, convex, shining, above variable* 

 from pale yellowish testaceous to brownish testaceous, head entirely piceons, ex- 

 cept a pale space in front of each eye, the clypeus of % usually paler than the 

 female. Thorax rather sparsely and indistinctly punctate, the punctures sepa- 

 rated by two or three times their own diameters, the arcuate and transverse 

 rows of coarser punctures very indistinct, basal marginal line either very indis- 

 tinct or absent. Elytra punctured similarly to the thorax, the punctures more 

 distant near the apex, the usual rows of coarser punctures scarcely discernible. 

 Body beneath piceous, opaque ; femora piceons, tibise and tarsi rufo-testaceous. 

 Length .14— .18 inch. ; 3.5—4 5 mm. PI. iii. fig. 13. 



The presternum is distinctly carinate longitudinally, the carina more elevated 

 in front. 



The mesosternal lamina is prominent, but somewhat variable in 

 form sexually and individually. In the male the lamina is some- 

 what triangular in form, the free edges oblique, the angle acute. In 

 the female the lamina is more nearly square, the lower edge slightly 

 oblique, the front either slightly oblique, or nearly vertical, the angle 

 sometimes slightly raucronate. 



In the male the claws of the front feet are dissimilar, the anterior 

 claw having a moderate quadrangular tooth, the posterior simply 

 angulate at base. The claws of the middle feet are also dissimilar, 



•■■ The variability in color seems due rather to the mode of collection and 

 preservation than to an actual difference in nature. 



