The Pselaphid^ of North America. 7 



2* Prothorax without discal crests; $ last segment pointed, vertical fovea 

 nude. (Pacific coast species). 



33 Shoulders hanging, ohsolete, intermediate elytral basal fovea confluent 

 with the internal one. 



Vertex with a central impression, occiput with a rounded tubercle ; 

 prothorax with the median sulcus merely indicated near the 

 median fovea. Length 1.9 mm. British Columbia. 



albio7iicHS. 

 Vertex not impressed in the center, prothoracic median sulcus 

 nearly entire. Length 1.9 mm. Middle California. 



occidiiHS. 



3* Shoulders moderately prominent, rounded ; ^ last ventral with a large 

 crater shaped fovea. , 



Black, legs and antenna brown, occiput carinate; prothorax with- 

 out a trace of median sulcus, elytral basal fovese separate, 

 conspicuous. Length 2.2 mm. Middle California. 



vionticola. 



Rust-red or piceous-red, elytra brighter, occiput carinate, protho- 

 rax with an anteriorly abbreviated sulcus; intermediate ely- 

 tral basal fovese nearly obsolete. $ with the fovea on the last 

 ventral, large, crater shaped. Length 2.2 mm. Washington, 

 Oregon, California, Vancouver Island. - zep/iyrinus. 



31 Shoulders angular, armed with a minute, blunt tubercle; elytra with 

 shallow, irregular, scar-like impressions; elytral basal fovese separate, 

 conspicuous. Length i.S mm. Middle California. - cicatricosus. 



21 Prothorax with discal crests. 2 last abdominar segment rounded. 

 (Eastern species.) 



Elytra strongly punctate, shoulders acutely angulate, $ last anten- 

 nal joint toothed at the base; occipital fovete nude. Length 

 i.o mm. Pennsylvania, Illinois. - - - sckaumii. 



ii Frontal margin in the $ separated from the clypeus by a sulcus or exca- 

 vation; in the 2 continuous with the clypeus. (Atlantic slope.) 



4* Frontal margin produced {i) beyond the inter-antennal line. 



5* Vertex slightly scabrous, vaulted and carinate; .*, last antennal joint 

 long, with an erect tooth ; elytra punctate, shoulders not armed ; ver- 

 tical fovese nude. Length 1.5 mm. Pennsylvania, Illinois, riparius. 



58 Vertex coarsely scabrous, not vaulted, occiput carinate, circumambient 

 sulcus obsolete, prothorax trisulcate; ^ last antennal joint without a 

 tooth. 



62 Frontal margin (r) notched in the middle, overhanging the clypeus; 

 occiput carinate, occipital fovese nude; shoulders angulate; head 

 orthognathous. Length 2.2 mm. Pennsylvania, Illinois, scabriceps. 



