3d NORTH AMERICAN 



broadly, roundly, and rather strongly emarginate behind ; suture very 

 slightly longer than the pronotum ; surface convex, very feebly impressed 

 on the suture at the base, rather finely, very deeply, exceedingly closely 

 and irregularly channeled. Abdominal segments decreasing uniformly and 

 rapidly in width, first distinctly narrower than the contiguous elytra ; surface 

 finely, very closely, and evenly punctulate ; transverse carinae tricuspid, 

 middle cusps fine and aciculate, lateral very short. Legs short and robust, 

 pale piceo-rufous ; first joint of posterior tarsi two-thirds as long again as 

 the second, and as long as the last, joints two to four uniformly and rapidly 

 decreasing in length. 



Male. — Second, third, and fourth ventral segments having in the middle 

 and at the apex a small triangular area, which is lustreless and very minutely 

 reticulated; fifth segment emarginate in its middle fourth at apex, emargi- 

 nation evenly rounded, eight times as wide as deep, contiguous surface 

 feebly impressed ; sixth segment triangularly incised at the apex, incisure 

 slightly wider than deep ; seventh segment broadly and triangularly emar- 

 ginate at apex. 



Female. — Sixth segment broadly and evenly rounded behind. 



Length 3.4-4.2 mm. 



Detroit, Michigan, 10; Illinois, 1 ; Washington, D. C, 1 ; Grimsby, 

 Ontario, 2. 



A very distinct species in many ways, more especially, however, in 

 the curious triangular patches at the apices of the ventral segments 

 in the male. The male sexual characters seem to vary not a little 

 in degree, and specimens are seen in which the emargination of the 

 fifth segment is just perceptible, and in which the angle of the incisure 

 at the apex of the sixth segment is distinctly rounded. Definite 

 varieties or subspecies may be indicated by these variations. 



19. S. tacomae n. sp. — Form very moderately robust. Pubescence fine, 

 very sparse, except along the sides of the abdomen, short, semi-erect, flavo- 

 cinereous. Head moderate, twice as wide as long ; interocular surface rather 

 deeply excavated, nearly three times as wide as the eye, equally trilobed by 

 the longitudinal sulcations, which are feeble ; intermediate surface feebly 

 and evenly convex, punctures rather fine ; ocular lines meeting at about one 

 length in advance, strongly curvate ; antennae longer than width of head. 

 robust, black, club distinct ; third joint fully one-half as long again as the 

 fourth, fourth and fifth equal, sixth slightly longer and distinctly less robust 

 than the seventh, eighth nearly twice as long as wide, cordate, joints of club 

 of nearly equal width, slightly increasing in length. Prothorax widest 

 slightly before the middle, where it is distinctly narrower than long ; sides 

 thence very moderately convergent posteriorly ; anterior margin slightly 

 longer and more arcuate than the pdsterior ; surface nearly evenly convex, 

 very finely, exceedingly closely, and irregularly punctured and channeled, 

 interspaces acute; canaliculation very short and feeble, beginning slightly 

 before the middle, and equal in length to one-third that of the pronotum. 

 Elytra at base as wide as the head ; sides nearly parallel, much longer than 



