oGQ Mr. T. D. A. Cockerell — Descriptions and 



shining than in 0. nigrifrons, the hind margins concolorons. 

 Head large ; clypeus normal ; mandibles 4-dentate, the 

 inner .two teeth very short ; near the interval between the 

 first and second teeth is a little patch of shining orange liair ; 

 antenna black; hair o£ face black and dull white, tlie black 

 coarse and mainly on the clypeus and above, the white prin- 

 cipally at sides ; black hairs about ocelli, but hair on top of 

 head dull white ; cheeks with black hair, but anteriorly bare, 

 with a very little short white hair which glistens in certain 

 lights ; thorax above with yellowish-white hair, not mixed 

 with black ; hair of pleura short and scanty, dark, a little 

 light above posteriorly. Legs black, with black hair ; 

 tegulse black, with a blue spot. Wings broadly dusky on 

 apical margin; first r. n. joining second s.m. about 1| as far 

 from base as second from apex. Abdomen with light hair on 

 first segment and middle of second ; otherwise the hair is 

 black except that the apex of the last segment is covered 

 with chocolate-brown tomentum ; scopa black. 



This may prove to be the female of 0. cyaneonitens, CklL, 

 which ( (J ) was also found at Boulder by my wife, June 4, 

 9, and 10, 1905. 



Hah. Boulder, Colorado, June 10, 1905 [W. P. Cockerell). 



Osmia hypochrysea Rohweri, subsp. n. 



$ . — Length about 10 mm. 



Differs from true hypochrysea in being somewhat larger 

 and more robust, the patch of orange hair on the mandibles 

 little developed, the hair on inner side of hind tarsi dark 

 ferruginous (black in type). The clypeus is quadridentate 

 as in the type. 



Hah. Boulder, Colorado, May 1906 {S. A. Rohwer). 



The locality is more than 2500 ft, lower than that of the 

 typical form. 



Osmia hypoleucoy sp. n. [pentstemonis^ subsp. ?). 



$ . — Length about 7^ mm.; anterior wing 5^; width of 

 abdomen about 2^. 



Head and thorax deep blue ; abdomen brilliant purple- 

 blue, the hind margins of tlie segments broadly olive-green ; 

 head and thorax very densely punctured, their hair long and 

 coarse, but not dense, black on head except on occiput and a 

 little on hindmost part of cheeks, dull white mixed with 

 black on thorax above, light on tubercles, black on upper, 

 but white on lower part of pleura. Head oblong, clypeus 



