The Pselaphid^ of North America. 5 



the head, including the eyes, very convex both waj's, widest 

 in the middle; sides strongly and evenly arcuate, shoulders 

 not prominent. Disk narrowly elevated at the base, with 

 three very small punctures on each elytron, sutural interval 

 punctured, discal lines wanting. Abdomen with the last seg- 

 ment rounded at tip, last ventral with a deep transverse tri- 

 angular cavity, sHghtly elevated in the middle at the bottom. 

 Anterior tibiae of ^ gradually dilated from the knee to the 

 anterior third and emarginate above from this point to the 

 end, leaving a strong sharp tooth. Tarsi with the second 

 and third joints equal in length, intermediate tibiae with a 

 terminal spine, posterior tibiae arcuate. $ with head evenly 

 convex posteriorly, somewhat roof- shaped anteriorly, the 

 highest part rounded, the foveas as in the 6, the antennal 

 tubercles nearly obsolete, the frontal margin triangularly pro- 

 duced from the margin to the middle. Elytra very convex 

 longitudinally, shoulders less prominent and the disk much 

 shorter than in the 6; the first abdominal segment is slightly 

 longer than in the 3, the last aculeate, the last ventral semi- 

 circular at the base. The genital sht is straight at the sides, 

 angulate at the middle, and in the middle of the area is a 

 large flat-bottomed, triangular depression, leaving large, oval, 

 convex, obHque elevations at the sides. Antenna and legs 

 simple and straight. 



Plate IX, Fig. 76 ?; 77 ?, a. b. c. 



For a knowledge of the ? I am indebted to Mr. Henry 

 Ulke, who found them in considerable numbers near Wash- 

 ington. It seems to be confined to the iVtlantic States. 



Batrisus, Aiibe, 



Form of the body circulo-cyHndroid, narrow, elongate, 

 abdominal margins not parallel to each other, the outer edge 

 rounded not reflexed; the inner one obhque, causing the bor- 

 der of each elytron to appear triangular; the base of the 

 dorsum is trifoveate, the elytra very convex, the discal lines 

 never reaching beyond the middle. Prothorax with two or 



