NORTH AMERICAN COLEOPTERA. 199 



California; (Sonoma Co. 2). 



The type is a male; the abdominal sexual characters are 

 not very well marked and consist of a very small transverse 

 impression beneath, near the apex. The under surface of the 

 head is moderately convex, with a fine but distinct median 

 carina; it is coarsely, rather deeply and not densely 

 punctate. 



The female which I have associated with this male is very 

 slightly more depressed and very slightly more robust; the 

 antennee are shorter and more robust; the under surface of 

 the head is more finely and feebly punctate; the median 

 pronotal channel is finer and not so distinctly dilated in the 

 middle; the elytral striae are more feebly impressed; the 

 pubescence of the body is slightly denser and the color is 

 paler, especially that of the elytra, w^hich is rather bright 

 rufous. If the specimen were not a female I should not 

 hesitate to describe it as distinct, but as the sexual char- 

 acters in this genus are not known the above difi'erences 

 may be due simply to the usual sexual modification. The 

 material before me is so limited that very little can be learned 

 of specific variability, but in tabulating the species above 

 I have made use only of those characters w^hicli are regarded 

 as of great importance in other portions of the Pselaphid?e. 



0. interruptus n. sp. — Moderately robust, convex, uniformly dark rufous; 

 legs and antennte very slightly paler; pubescence rather coarse, not long, 

 moderately dense; integuments shining, pronotum slightly duller. Head 

 much wider than long; eyes moderate, convex, at their own length from the 

 base; sides behind them strongly convergent and arcuate to the neck, which 

 is deeply impressed, broadly sinuate; occipital foveas on a line through the 

 anterior limits of the eyes; occiput with a narrow median canaliculation; 

 antennae rather robust, as long as the head and prothorax together; basal 

 joint slightly robust, a little longer than wide, second very slightly narrower, 

 cylindrical, scarcely as wide as long, three to eight very slightly narrower, 

 decreasing in length, third distinctly wider than long, nine and ten rather 

 abruptly longer and much wider, transverse, tenth distinctly longer and 

 slightly wider than the ninth, eleventh more robust than the tenth, elon- 

 gate, conoidal, slightly obliquely pointed, scarcely as long as the four 

 preceding together. Prothorax widest at a little more than one-third its 



