340 PROCEEDINGS OF THE ACADEMY OF [1897. 



Wash., differs by having a brassy-green abdomen ; it appears to be 

 only a variety of this species. 



I have not described the $ of 0. nanula, but I have before me 

 a series of nine males, collected by Mr. Kincaid at Seattle and 



■lyrnpia, which I believe belong here. They average slightly 

 smaller than the females, and are of a brassy-green color. They 



~ight readily be confused with small examples of inurbana, but the 



sixth abdominal segment is entire or very feebly notched. The dor- 



1 pubescence of the thorax and head is quite brightly colored, 



and not mixed with black. The smaller size and the absence of 



the ventral tooth at once separate them from odontogaster. 



Osmia tristella n. sp. 



9 . Length 7 to 8 mm., of ordinary build, the abdomen somewhat 

 longer than in 0. nanula. Head, thorax and abdomen dark indigo 

 blue ; legs, mandibles and antenna? black. Head of ordinary size, 

 not so large as in nanula. Pubescence black, not dense, long on 

 head and thorax, white just behind wings and at sides of first ab- 

 dominal segment subbasally ; there is also some obscure white or 

 whitish pile on the last dorsal segment of the abdomen. The 

 pubescence of the face, vertex, thoracic dorsum and ventral scopa is 

 iv holly black. The abdominal segments between the first and last 

 are shining, and present some short pile, wholly black except for an 

 occasional short pale hair. The pubescence of the legs is all black. 

 Punctuation ordinary, very dense on vertex and mesothorax ; basal 

 area of metathorax minutely roughened, not shining. Clypeus or- 

 dinary ; tegula? black. Wings pale fuscous; second submarginal 

 cell about as long as the first on the cubital nervure ; first recur- 

 rent nervure joining second submarginal cell at the end of its basal 

 sixth, second at the beginning of its apical sixth. 



Hab. — Olympia, Wash., 2 9, one June 30th (T. Kincaid); 

 Seattle, Wash., 4 9 , April 18th and May 11th (T. Kincaid). This 

 might be confused with nanula, but is easily separated by the char- 

 acters italicized. 



Osmia cyanella n. sp. 



9 . Length 9 mm., stoutly built, very broad, with a large sub- 

 quadrate head. The thorax is especially broad, the distance between 

 the wings being much greater than in tristella or nanula. The ab- 

 domen is suboval. Color of head, thorax and abdomen dark indigo 

 blue ; legs, antenna? and mandibles black. Pubescence, including 



