NORTH AMERICAN COLEOPTERA. 259 



Occurs in Vermont (Roberts), Massachusetts (Blanchard), Penn- 

 sylvania (Hamilton) and District of Columbia (Ulke). 



€'. lacustris Lee — Oval, decidedly oblong, moderately convex, piceons, 

 shining, entire border indeterminately paler. Thorax relatively coarsely and 

 closely punctate, more sparsely and less deeply at the sides, the arcuate and 

 transverse rows of coarse punctures very evident. Elytra punctured similarly 

 to the thorax, but a little less closely and somewhat more sparsely toward the 

 apex, the usual series of coarse punctures never present, except by very rare 

 exception, sutural stria extending nearly three-fourths to base. Body beneath 

 opaque black. Femora opaque, piceons, tibiae and tarsi rufo-piceous. Length 

 .16— .18 inch. ; 4—4.5 mm. 



The prosternum is simple, the mesosternum has a very short, transverse, ele- 

 vated line. 



The claws are similar in the sexes, slender, feebly arcuate, slightly broadened 

 at base. 



This is the smallest species of the genus at present known in our 

 fauna. Its essential characters are — the oblong form, the ab.sent 

 serial coarse punctures of the elytra, and very short transverse ridge 

 of mesosternum. It will also be observed that the last two joints of 

 the maxillary palpi differ very little in length, the terminal joint 

 being only slightly shorter than the preceding. 



Occurs in the Lake Superior and Canadian region, eastward to 

 the New England States. 



HELOCOi^BUS n.g. 



Tarsi heteromerous with the formula 5-4-4. Maxillary palpi 

 very long and slender, the pseudo-basal joint curved with the con- 

 cavity in front, the last joint very distinctly shorter than the pre- 

 ceding. Mesosternum with a broad pyramidal process, when viewed 

 fi'om behind elevated like a narrow A and acute at apex. Femora 

 punctured, opaque and jjubescent. Tarsal claws distinctly toothed 

 in the male, rather widely dilated at base in the female. PI. iii, fig. 15. 



The thorax has no basal marginal line. Elytra deeply striate, the 

 striae entire, except the sutural and the second, no scutellar stria, 

 interstices without the three or four series of coarse punctures. 



This genus, founded on Phihjdrus bifidus Lee, is, to a certain ex- 

 tent, intermediate between Cymbiodyta and Philydrus. It has the 

 tarsi and pseudo-basal palpus joint of the former and the toothed 

 claws of the greater number of the. latter. The mesosternum is 

 peculiar in its protuberance, being structurally a great exaggeration 

 of the form foreshadowed in H. fratercidus and rotuudatus, as has 

 been indicated in the remarks under Cymbiodyta. 



