NORTH AMERICAN COLEOPTKRA. 63 



Elytra regularly narrow ovate, front deeply oxeavate lu-t ween the eves. 2 2.2') mm. 



cavifrons. 



Elytra more robust, ovate, globose, or sub-equal. 



Striae of elytra fine, shallow, punctures distant; distinotlv ])ul)eseent, elytra 



nearly twice as long as wide, 2.5 mm confertum. 



Striae of elytra deeper, punctures more approximate, intervals moderatelv wide 

 flat. 



Form robust, humeri large, sides of elytra sub-equal, not at all or very 



sparsely pubescent, .3 — .'i.a mm rostrum. 



Form moderate, humeri smaller, elytra more ovate, distinctly pubescent, 



2— 2.5 mm .".nigrum. 



Striae deep, intervals convex, punctures large and profound. 



Humeri small, form moderate, intervals of elytra wider than stria, 1 — 5 mm. 



patruele. 



Humeri large, form broad, obese, striae as wide, or wider than intervals, 2 mm. 



porcatum. 



A. cavifroiis Lee Pac. R. R. Expl. and Surv. Ins. 5.3.— Black, basal joints 

 of antennae yellow, very sparsely pubescent, form ovate. Head short, broad, punc- 

 tured and rugose ; front excavated between the eyes ; rostrum short, stout and 

 .somewhat decreasing in thickness to near tip. Antennae long and slender; basal 

 and second joints equal, and yellow. Thorax transverse, widest beliind middle; 

 base bisinuate, moderately punctate, with a distinct impressed line, foveate at 

 base. Elytra regularly ovate, humeri indistinct; striae distinct, punctured; inter- 

 vals wide, flat and finely punctured. Beneath rather sparselv punctured. 

 Length 2—2.25 mm. 



Hab.—W. T., Cal., Hudson Bay. 



Rathei- widely distributed, but very few specimens received. The 

 species is easily distinguished by the general form from all others in tliis 

 section, agreeing almost entirely in that respect with the group crassina- 

 sum of section -t, and the thorax is less decidedly narrowed at base than 

 in the others of this section. It is peculiar in having two joints of the 

 antennae pale, and in the large deep excavation of front. 



A. confertum n. sp.— Black, densely clothed with white pubescence; form 

 robust, somewhat depressed. Head broad, short, coarsely punctured, longitudi- 

 nally rugose; eyes large, prominent: antennae inserted close to base, short and 

 stout; first and second joints sub-equal. Thorax transverse, densely and coarsely 

 punctured, with a short foveate line at base. Elytra oblong, one-half longer than 

 wide, humeri evident, distinct, sides equal ; striae moderate, distinctly punctured ; 

 intervals wide, flat and finely scaljnnis. Beneath moderately punctate. Length 

 2 — 2.5 mm. 



Ifab. — Western and Southern States. 



The dense pubescence anil depressed elong;ito form distinguish this 

 species. 



A. rostrum Say, Journ. Ac. v, 25.'{, Cure. p. 6. Sai/i Gyll. Sch. Cure, v, 252, 

 Harris, Iiij. Ins. p. 67. — Black, spa^'sely or not at all pubescent. Head transverse, 

 rugose and ]iunctured ; eyes distincl. proininent, moderate in size; rostrum slightlv 



