384 Coleopter^ological Notices, V. 



Elytra but slightly longer than the prothorax ; abdomen polished, very 



remotely and obsoletely punctulate nanus 



exiguus 

 Elytra much longer than the prothorax ; form broader, the abdomen strongly 

 reticulate, tinely, more densely and subgranularly punctulate. 



tetracarinatus 



It will be observed that the species are not quite as abundant 

 as in the European fauna, but others will probably be discovered 

 as these obscure little insects are seldom collected. Four of the 

 twenty -three are common to the two continents. 



O. SCUlptus Grav. — Mon., p. 191 ; mosrens Mels. : Proc. Ac. Phila., II, 

 p. 42 ; antennatiis Steph. ; lonyicornis Mann. ; testaceipennis Fairm. 



The head in both sexes is small, narrower than the prothorax, 

 with a single median impressed channel toward base and large 

 eyes. The prothorax is moderately transverse, with three distinct 

 impressed channels, the elytra increasing in width from base to 

 apex, a little wider and much longer than the prothorax, rather 

 coarsely, subrugosely sculptured. The mentuni has a fine arcuate 

 discal groove extending from one basal angle to the other. Length 

 3.4-4 mm.; width 1.0-1.1 mm. 



This species is represented in my cabinet from Iowa, Wisconsin, 

 California and Europe. The European and American forms do 

 not differ at all. The male appears to be much less abundant than 

 the female. 



O. insignitus Grav. — Mon., p. 188; americanus Mann.: Brachel., p. 48. 



In the male of this species the head is large, slightly wider than 

 long, with the eyes at their own length from the basal angles, the 

 antennae about one-third longer than the head, exclusive of the man- 

 dibles, the latter very long, decussate, almost evenl}^ arcuate and 

 acutely pointed, the frontal porrect process acute and simple. In 

 the female the head is very much smaller, transverse, with the 

 frontal margin not armed, the eyes about equally large but almost 

 attaining the base, the antennae fully one-half longer than the head 

 and the mandibles much smaller, thicker and more strongly arcuate. 

 The mandibular tooth is situated at nearly the same distance from 

 the base in both sexes, but is very much nearer the apex in the 

 female. In the male the head, prothorax and elytra are nearly 

 equal in width and the elytra are distinctly longer than the pro- 

 thorax, strongly and rather closely punctured. It occurs through- 



