COLEOPTEKA. 65 



semi-recumbent, piceons setae; sixth segment sinuate at apex, sinus some- 

 what more broadly rounded than the apices, tour times as wide as deep. 



Female. — Sixth segment evenly rounded behind throughout. 



Length 2.6—2.9 mm. 



Cambridge, Massachusetts, 4; Detroit, Michigan,?; White Fish 

 Point, Lake Superior, 1. 



46. S. placidiis n. sp. — Form moderately slender. Pubescence very 

 short, fine, sparse, recumbent, cinereous, scarcely visible. Head robust, 

 scarcely twice as wide as long ; interocular surface twice as wide as the eye. 

 moderately excavated, equally trilobed by the rounded, but conspicuous sul- 

 cations ; intermediate surface evenly and rather strongly convex ; punctures 

 rather coarse, (dose, and evenly distributed; ocular lines meeting at one 

 length in advance; antennae slender, longer than the width of head, first 

 joint black, remainder dark piceous-brown, club distinct ; third joint one- 

 third as long again as the fourth, fourth and fifth sub-equal, sixth and 

 seventh equal in length, the latter thicker, eighth slightly longer than wide, 

 joints of club uniformly increasing in length and thickness ; maxillary palpi 

 piceous-brown, first joint flavo-testaceous. Prothorax robust, widest just 

 before the middle, where it is four-fifths as wide as the head, and about as 

 broad as long; sides thence very moderately convergent posteriorly and 

 nearly straight; anterior and posterior margins equal in length, the former 

 much the more arcuate ; surface feebly tuberculate along the sides, especially 

 toward the base, very closely, rather finely and somewhat evenly punctate; 

 canaliculation very obscure, being merely a slight, irregular erosion, com- 

 mencing before the middle, one-third as long as the pronotum. Elytra at 

 base just perceptibly narrower than the head; sides rather strongly diver- 

 gent posteriorly, very feebly arcuate, equal in length to the width at base ; 

 together broadly, rather strongly and triangularly emarginate behind ; suture 

 slightly longer than the pronotum ; surface somewhat depressed, nearly even, 

 coarsely, closely, irregularly, and sub-vai iolately punctured ; punctures more 

 isolated near the inner basal angles. Abdominal segments decreasing uni- 

 formly and somewhat rapidly in width, first a little narrower than the con- 

 tiguous elytra ; surface broadly convex, rather coarsely, closely, and evenly 

 puuctulate ; transverse carinae tricuspid, lateral cusps short, broad, and 

 rudimentary, middle long, finely aciculate, conspicuous. Legs rather short 

 and robust, fuscous, under sides of femora nearly rufous ; first joint of poste- 

 rior tarsi two-thirds as long again as the second, as long as the last, second 

 distinctly longer than the third. 



Male. — Posterior edge of the fifth ventral segment just perceptibly incur- 

 vate in the middle ; sixth segment feebly sinuate at apex, sinus rather broad 

 and extremely feeble. 



Female. — Sixth ventral segment evenly rounded behind. 



Length 2.5-2.7 mm. 



Detroit, Michigan, lb 



The sexual characters of this species are very feeble, hut still of 

 such a nature as to be almost unmistakable ; the sixth segment is 

 Stenini. 5 



