BEES OF BOULDER COUNTY, COLORADO 2$ I 



clypeus with a strong, smooth and shining, longitudinal median ridge (Boulder, 



June, W. P. cm.) hypocrita Cldl. 



Very brilliant blue or green; scopa black 2. 



Dark blue or green, or black with blue or purple tints 3. 



2. Abdomen long and parallel-sided; tegulae piceous with a green spot in front (Ward, 



fls. Edwinia) fulgida Cresson 



Abdomen shorter; tegulae wholly green (Boulder) bruneri Ckll. 



3. Large species; hair of thorax above bright fox-red; hair of clypeus and adjacent 

 sides of face black; scopa black (Boulder, June, W. P. Ckll.) novomezicana Ckll. 

 Hair of thorax above not thus briUiant 4. 



4. Pubescence, including ventral scopa, white (Boulder, June, W. P. Ckll.) 



hesperella Ckll. 

 Ventral scopa reddish; edge of clypeus 4-dentate (Boulder, May, Rohwer) 



hypochrysea rohweri Ckll. 

 Ventral scopa black 5. 



5. Hair of pleura white 6. 



Hair of pleura black (white in lower part in one small species, hypoleuca)g. 



6. Hair of face all white (Boulder, June, W. P. Ckll.). . . . coloradella Ckll. 

 Hair of face not, or not all, white; small species 7. 



7. Legs metallic; vertex and face with very coarse black bristles (Ward, July, fls. 



Pentstemon) pentstemonis Ckll. 



Legs black 8. 



8. Scutellum with long black hairs among the white; front brightly colored (Ward, 

 July, fls. Phacelia: Boulder, June, 17, W. P. Ckll.) .... phaceliae Ckll. 

 Scutellum without black hairs; front black or very dark (Ward, July, fls. Phacelia) 



melanotricha Lovell & Cockerell 



9. Thorax above with white hair; large species 10. 



Thorax above with black hairs among the light 12. 



10. Mandibles 4-dentate, massive; hair of pleura very short and scanty (Boulder, 



June 10, W. P. Ckll.) brevihirta CkU. 



Mandibles 3 -dentate; hair of pleura long il. 



11. Second abdominal segment with much hair; abdomen dark blue (Boulder, June 9, 



Ckll.; June 17, W. P. Ckll.) nigrifrons Cresson, var. 



Second abdominal segment with black hair; abdomen very shiny, green, with the 

 hind margins of the segments purple (Arapahoe Peak, Sept. i, Rohwer) 



hendersoni Ckll. 



12. Mandibles 3-dentate 13. 



Mandibles 4-dentate 16. 



13. Large species 14. 



Small or rather small species 1 5- 



14. (Colorado, etc.) nigrifrons Cresson 



Differing from nigrifrons by having the punctures of the third abdominal segment 

 much more distinct and separate; the hair at sides of metathorax white; a tuft of 

 long white hair on and around tubercles; and the sides of face greener. No ap- 

 pressed light hair on cheeks. Length about 11 1 mm. (Boulder, fls. Gaillardia, 

 July 6, W. P. Ckll.) gaillardiae Ckll. 



