AMERICAN COLEOPTERA. 329 



disc convex, sparsely and finely punctured. Elytra cylindrical, parallel, 

 convex, sutural striae impressed at apical half, surface with rows of moderate 

 punctures which become obsolete near the tip. Prothorax beneath smooth, 

 metathorax and abdomen sparsely and finely punctured, last ventral more evi- 

 dently punctured. Pygidium sparsely punctate. Length .18 inch; 4.5 mm. 



This is the largest species in our fauna. In the male the head is 

 larger than in the female and rather broader than the thorax, in both 

 the front is convex without impressions and the mandibles of the male 

 are rather more prominent than the female. 



Occurs in Tennessee and Greorgia. 



R. (limidiatus Mann. — Elongate, subcylindrical, piceous, base of elytra, 

 head and legs rufous. Head sparsely punctulate, front slightly impressed ou 

 each side. Antennae with third joint hardly equal to the next two united. 

 Thorax longer than wide, rather sparsely and finely punctate, sides very feebly 

 arcuate in both sexes, narrowed slightly to base in male. Elytra slightly 

 wider than the thorax, subcylindrical, sides at apical half slightly narrowing 

 to apex, sutural striae at aj)ical half slightly impressed, disc with rows of fine 

 punctures becoming rapidly obsolete to apex. Prosternum at middle sparsely 

 punctured, sides and side pieces coarsely punctured. Abdomen sparsely and 

 equally punctate. Pygidium moderately punctate. Length .14 — .16 inch; 

 3.5 — 4 mm. 



As in the preceding species the male has the head larger than the 

 female but not much so. Its color varies somewhat in the extent 

 of the rufous portion of the elytra but greater or less traces always 

 remain of that color. 



Occurs from Alaska to Lake Superior, and Mount Washington, 

 New Hampshire, (Blanchard). 



R. briiuneus Horn. — Uniformly brownish, moderately shining. Head 

 sparsely punctate. Thorax a little longer than wide, apex and base truncate, 

 sides subparallel at middle, slightly arcuate at base and apex, disc convex, 

 coarsely and sparsely punctured. Elytra slightly wider at base than the 

 thorax and feebly emarginate, disc with rows of moderately coarse punctures 

 which become somewhat finer toward the tip. Prosternum coarsely punctured, 

 side pieces nearly smooth. Metasternuin smooth at middle. Abdomen coarsely 

 and sparsely punctured, the first segment smooth at middle. Pygidium sparsely 

 punctate. Length .12 inch; 3 mm. 



Marquette, Lake Superior. The punctures of the entire surface 

 are coarser than in any other of our species. It must be considered 

 the intermediate form between those with the long and those with the 

 broad thorax. 



R. bipuiictatus Say. — Elongate, cylindrical, black shining, antennae 

 and legs rufous, elytra each with two rufous spots, one oblique behind the base, 

 the other smaller, oval at apical third. Head sparsely punctate. Antennae 

 with third joint hardly ae long as the next two combined. Thorax longer 

 than wide, sides very feebly arcuate, not perceptibly narrowed posteriorly, 

 disc convex sparsely punctulate. Elytra not wider than thorax, cylindrical, 

 parallel, sutural stria impressed at apical half, surface with rows of moderate 



TBANS. AMI'.K. ENT. SOC. VII. (42) OCTOBER, 1879. 



