222 CALIFORNIA ACADEMY OF SCIENCES. 



aud prothorax, tenth joint nearly square, preceding scarcely as broad as 

 long. Head slightly longer than wide, sides behind the eyes nearly par- 

 allel, surface coarsely punctate, with a median smooth space. Prothorax 

 one-half longer than wide, scarcely as wide as the head, distinctly narrowed 

 behind; sides more sparsely and a little less coarsely punctate than the 

 head. Elytra wider than the prothorax, not or but very little longer, 

 longer than wide, usually with distinct greenish lustre; finely, sparsely 

 punctate. Abdomen finely, moderately, densely punctate, moderately 

 shining, beneath a little more strongly punctate than above. 



In the male the front tarsi are rather strongly dilated, the last ventral 

 with a small triangular emargination, which is broader than deep, and a 

 triangular impression. 



In the female the front tarsi are moderately dilated, the last ventral 

 entire. 



Length, 3.5-6.5 mm. 



Pasadena and Pomona. Found along the margins of 

 streams; March to October. 



A. formosus is allied to A. pcederoides and A. elegan- 

 tulus, but is larger than either and of a different color, 

 which remains constant in the ten examples studied. 

 The abdominal punctuation is much closer than in A. 

 elegantulus, but less dense than in A. pcederoides. It 

 differs from the latter species also in its longer thorax, 

 which is more narrowed behind. 



Orus. 



The species of this genus inhabit the true Pacific 

 Coast region of California, and if secondary sexual 

 characters are reliable, there are several species to add 

 to the two described by Casey. The following three 

 species are very close to 0. punctatus, and while there 

 are discoverable small differences in details, these are 

 difficult to express in description, and however labor- 

 iously described it is practically certain that the col- 

 lector would find it quite impossible to identify his speci- 

 mens without reference to the male sexual characters. 



