lircorJs of lieen. 3<)3 



with a <;ood deal of light hair ; sixth sef^ment entire or witli 

 the faintest su<;gi'stion of a notch ; seventh bidcntate ; first 

 ventral segment subemarginate ; third emarginate, witli a 

 tuft of orange hair in the tiotch. 



In Robeitsdn'd table of genera segregated from Osmia this 

 runs to \\, and rnns out because of the structure of the sixth 

 abdominal segment. Because of its coh)ration it could be 

 mistaken for 0. tnurhatia,CTef^;*., but it is easily known from 

 that by the coarse black hair on the abdomen &c. It is also 

 exceedingly like 0. Latreillet, Spinola (which I have from 

 Tangier), but is known from that by the same characters 

 which separate it from t'nurbana*. 



Hah. Boulder, Colorado, at flowers of Pulsatilla hirsutis- 

 sima, April 20, 1906 ( IV. I\ Cockerell). 



Osmia i^ulsatillce, sp. n. 



c? . — Length about 7.] mm.; anterior wing about 5 ; width 

 of abdomen 2\. 



Green, the iiead and thorax above rather yellowish green, 

 the abdomen blue-green (Prussian green). Head normal, 

 eyes prominent, mandibles with two widely divergent teeth ; 

 face covered with dull white hair, with some long black hairs 

 at sides and many long black hairs on front and vertex ; hair 

 of cheeks white, with black hairs immediately adjacent to 

 the eye. Antenna? rather long, black ; flagellum normal ; 

 liair of thorax long and dull white, dorsally with black 

 haiis intermixed; mesothorax dull, with exceedingly dense 

 }>unctures; tegulae largely green. Wings dusky ; first r. n. 

 joining second s.m. about Ij^ as far from base as second from 

 apex. Legs dark green, with dull white hair, that on inner 

 side of liind basitarsus dark fuscous; spurs normal. Abdo- 

 men with white hair on first three segments, long only on 

 first ; the other segments have the hair mixed black and 

 silvery, but short and inconspicuous ; sixth segment entire ; 

 seventh bidentate; ventral segments normal, second apically 

 with fine white hair. 



This is an Osmia s. str. in the sense of Robertson. It is 

 very like O. prcxima^ Cresson, but is readily distinguished 

 by the mixture of daik hairs on the thorax above. Tlu; 

 abdomen is not so globular as in proxima, but is distinctly 

 parallel-sided. 



Itah. Boulder, Colorado, prox. 5.350 ft., at flinvers of 

 PuUatilla hirsutissima, April 20, 1906 (IF. 1\ Cockerel/). 



* An Alpfrinn ninlo of O. LadciUti, aljo boforo iin', lins the hair of 

 thf thoinx inurli rtdiler. 



