124 AMERICAN COLEOPTERA. 



oval, moderately finely striate; stride punctate to behind the middle, the first 

 and second nearly entire, the fifth represented by a slight groove at tip ; inter- 

 vals flat or nearly so, the third with the first dorsal puncture about one-third 

 from base, the second about one-third from apex. Beneath black, shining. Legs 

 rnfo-testaceous. Length .13-. 14 inch ; 3.25-3.5 mm. 



A very well-marked species, easily recognizable by the arrange- 

 ment of the frontal grooves. 



It is known to me from Canada, the Hudson Bay Territory, near 



Lowell, Mass. (Blanchard), Michigan, the Lake Superior region and 



Illinois. 



Group xvii. assimile. 



Head with the frontal grooves very deep, strongly convergent, 

 double, the inner groove long, the outer shorter and often feebly 

 marked; eyes large and prominent. Prothorax cordate or subcor- 

 date, truncate at base, the hind angles carinate. Elytra with the 

 strise abbreviated behind, the first and .second nearly entire, the fifth 

 represented by a slight groove at tip; dorsal punctures two, situated 

 on the third interval. 



The members of this group are quite easily recognizable by the 

 strongly convergent frontal grooves, the outer of which is usually 

 much shorter and less deep than the inner and often inconspicuous. 

 It is best marked in B. assimile. When we come to the definition 

 of the species, however, we find the task much more difficult. They 

 resemble eacli other closely, and are often difficult to separate. It 

 is hoped that the following table will affl)rd some assistance : 



Thorax distinctly wider than long : elytra about one-half wider than the thorax. 

 Hind angles of thorax acute, basal impressions unistriate; form slightly elon- 

 gate, convex; color black, scarcely seneous, the elytra usually finely 

 striato-punctate, with a subapical spot and the apex more or less testa- 

 ceous; legs varying from piceous to rufous. Length .13-. 16 inch. 



angulireriiiu Lee. 

 Hind angles of thorax rectangular. 



More elongate and less convex than nngidiferum ; elytra deeply striate, with- 

 out paler markings; basal impressions of thorax bistriate; legs black. 



Length .14.17 inch acutifroiis Lee. 



Less elongate, convex; color black, scarcely seueous, elytra often piceous, 

 with a subapical spot and the apex pale, moderately deeply striato-punc- 

 tate; basal impressions of thorax bistriate; legs rufous or rufo-piceous. 



Length .1'2-.15 inch oaiituin Lee. 



Scarcely convex ; color nearly as in cautam, the elytral markings often want- 

 ing; basal impressions of thorax unistriate; elytra rather more finely 

 striate ; legs varying from rufous to piceous. Length .12-.14 inch. 



coniiivens Lee. 



Thorax scarcely wider than long, hind angles rectangular; form convex ; color 



nigro-seneous, the elytra often brownish, deeply striato-punctate, with a 



subapical spot and the apex pale; legs testaceous. Length .08-. 11 inch. 



assimile Gyll 



