3G8 I\Ir. T. D. A. OockeveW^ Descriptions and 



ITah. Halfway House, Pike's Peak, Colorado, at flowers of 

 SaUx, May 30, 1904 {Cockerel}) . 

 The locality is 8400 ft. above sea-level. 



Osmia senior, sp. n. 



? . — Length about 12 mm.; widtli o£ abdomen 3|. 

 Abdomen approximately parallel-sided, broadest about the 

 apex of the third segment. Head dark blue below, green 

 above; mesothorax and scutellum green, pleura dark blue. 

 Abdomen blue-green, tlie margins of segments concolorous, 

 but segments 2 and 3 have an indistinct pinkish-purple band 

 across the middle, while 4 and 5 show coppery-red tints. 

 Head and thorax densely punctured, head rather large; 

 antennae black ; clypeus normal ; mandibles w^ith four very 

 distinct teeth, the apical one not very long ; hair of clypeus 

 black, of sides of face dull white, of front mixed white and 

 black, of vertex black, of occiput pale, of cheeks pale behind 

 and black in front ; hair of thorax above scanty, dull white 

 with black intermixed, of pleura black, but of tubercles 

 abundant and light, conspicuously contrasting ; tegulse rufo- 

 piceous, shaded with green. Wings dusky, iirst r. n. joining 

 second s.ra. about 1§ as far from base as second from apex. 

 Legs black, with black hair, the hind femora and coxaj very 

 faintly metallic ; middle femur with a few pale hairs apically 

 beneath. Abdomen with light hair on first segment and 

 short black hair on the others, each with a scarcely noticeable 

 subapical band of shining pale hairs, mostly failing in the 

 middle ; sixth with fine pale tomentum ; scopa black. 



0. gaillardice, Ckll., is allied, but larger, and without 

 appressed light hair on cheeks. The white hair at sides of 

 face separates 0. senior from 0. wardiana. By the colour 

 and shape of the abdomen 0. senior is like 0. densa, but that 

 has light hair on pleura. 



Hah. Boulder, Colorado, June 12, 1905 (IF. P. Cockerell). 



Osmia icardiana, sp. n. 



? . — Length a little over 12 mm; width of abdomen 4. 

 Kobust ; abdomen oblong. Head and thorax black, the 

 sides of face and supraclypeal area green, the scutellum and 

 liind part of mesothorax greenish ; middle of mesothorax 

 purplish black, with an area in which the strong punctures 

 are separated, showing the shining ground; head large, the 

 cheeks very full and rounded ; antennae black ; clypeus 

 somewhat produced, with the apex shallowly subemarginate ; 



