246 CALIFORNIA ACADEMY OF SCIENCES. 



uieri broadly rounded; disk depressed, with a feebly impressed line on each 

 ]iarallel and near the suture, minutely, evenly, very feebly and not very 

 densely punctate, slightly more than twice as long as the prothorax, one- 

 third longer than wide. Abdomen at base slightly narrower than the elytra; 

 sides convergent to the apex, strongly and evenly arcuate; extremely minutely, 

 densely and aspevately punctate. Legs slender; first joiut of the posterior 

 tarsi distiDctly longer than the next two together, ^much longer than the fiftb. 

 Length 3.0-3.7 mm. 



California; (Hoopa Val., Humboldt Co. 7). 



The type is a male, the sixth segment being broadly and 

 feebly emarginate at tip; in the female the prothorax is 

 much more distinctly wider than long and less strongly 

 cordate; the antennae are slightly shorter and do not attain 

 the middle of the elytra; in size the female is smaller than 

 the male. 



There is scarcety a trace of a median sulcation on the 

 pronotum, the sides of which are more deeply sinuate to- 

 ward the basal angles than in either densus or the Vancou- 

 ver representative of simulator. The species is chiefly re- 

 markable because of its slender form, sparse punctuation 

 Mud rufous legs. It was found in wet moss in the interior 

 of a flume for conveying spring-water. 



0. densus ^- sp. — Eather robust, depressed; body entirely black above and 

 beneath, oral organs rufo-testaceous; 1-gs fuscous throughout; antennae en- 

 tirelv piceous-black; pubescence cinereous, rather short, recumbent, extremely 

 dense; inte^iuments shining. Head moderate, slightly longer than wide; 

 sides behind the eyes strongly convergent to the neck and strongly arcuate; 

 eyes rather prominent, large, coarsely granulated, very densely setose; front 

 depressed, feebly biimpressed between the eyes, finely and densely punctate, 

 more sparsely so along the middle; antennae filiform, fully one-half as long as 

 the body; basal joint subcylindrical, three times as long as wide, second two- 

 thirds as long as the third, the latter slightly shorter than the first, joints 

 three to six equal, slender, six to ten gradually diminishing in length, the lat- 

 ter more than twice as long as wide, eleventh fusiform, slightly oblique at tip, 

 one-half longer than the tenth. Prothorax widest at the anterior third, where 

 it is distinctly wider than long and slightly wider than the head; sides strongly 

 arcuate, strongly convergent and distinctly and evenly sinuate toward the 

 basy; apex transversely truncate, about equal in width to the base which is 

 broadly, evenly and very feebly arcuate; basal angles slightly obtuse, very 

 narrowly rounded; disk transversely, evenly and moderately convex; impress- 



