COLEOrTERA. 113 



before the middle, where it is three-fourths as wide as the head, and one- 

 fourth narrower than long; sides thence moderately convergent and slightly 

 sinuous ; anterior and posterior margins equal in curvature, the former 

 noticeably longer ; surface strongly declivous at the sides ; rather finely, 

 somewhat irregularly punctate ; punctures deeply impressed and sometimes 

 coalescent ; interspaces nearly as wide as the punctures, very convex, highly 

 polished ; canaliculation long and narrow, sides somewhat irregularly out- 

 lined, terminating within very short distances of the margins. Elytra at base 

 as wide as the head ; sides very feebly divergent posteriorly and strongly 

 arcuate, longer than breadth at base ; together broadly and just perceptibly 

 emarginate behind ; suture very slightly longer than the pronotum ; surface 

 convex, impressed along the suture, more deeply so toward the base ; moder- 

 ately coarsely, deeply, and rather irregularly punctate ; punctures seldom 

 coalescent; interspaces generally as wide as the punctures, very convex, 

 highly polished. Abdominal segments decreasing uniformly and rather 

 rapidly in width, first scarcely as wide as the contiguous elytra ; surface very 

 convex, highly polished, sparsely and finely punctulate ; transverse carinae 

 4-cuspid, cusps equal in length and equidistant, aciculate and prominent, 

 intervals but slightly sinuate. Legs slender, moderate in length, black, 

 tarsi piceous-black ; first joint of posterior tarsi four-fifths as long again as 

 the second, second and third sub-equal, fifth as long as the first. Under 

 surface of the abdomen densely clothed with long, piceous, sub-recumbent 

 setae. 



Male. — Posterior edge of the fourth ventral segment emarginate in its 

 middle two-fifths, emargination evenly rounded and just perceptible, con- 

 tiguous surface feebly impressed for a short distance anteriorly; fifth emar- 

 ginate in its middle third at apex, emargination feeble and evenly rounded, 

 contiguous surface flattened throughout for the same width anteriorly ; sixth 

 segment sinuate at tip, sinus broad, evenly rounded, much wider than the 

 apices, six times as wide as deep ; seventh deeply emarginate at tip, bottom 

 of emargination transverse, sides produced in long, lateral, setigerous teeth. 



Female. — Sixth segment broadly truncate at tip, truncation arcuate ; tip of 

 seventh segment most irregularly, acutely, and deeply serrate. 



Length 3.1-4.0 mm. 



Cambridge, Massachusetts, 6; White Fish Point, Lake Superior, 3; 

 Isle Royale, Lake Superior, 1 ; Marquette, Michigan, 1. 



In the males the abdominal segments decrease much more rapidly 

 than in the females. 



I had already separated and described the Western specimens as 

 distinct, when I discovered that the characters upon which the sepa- 

 ration was based were so variable as to be comparatively valueless. 

 The tarsal structure varies considerably in the proportional lengths 

 of the first three joints ; the intervals of the carina! cusps are also by 

 no means constant. The sinus in the specimen from Isle Royale, 

 Lake Superior, is much deeper than in the others, and, as a rule,, the 

 Stenini. 8 



