252 UNIVERSITY OF COLORADO STUDIES 



15. Larger, length a little over 9 mm. ; lower part of pleura without white hair; legs not 



metallic (Ward, July, fls. Gilia) wilmattae Ckll. 



Smaller; lower part of pleura with white hair; legs metallic (Boulder, June 9, 

 W. P. Ckll.) hypoleuca Ckll. 



16. Small species; hair of sides of face mixed black and white (Halfway House, Pike's 



Peak, fls. Salix, May 30) pikei Ckll.* 



Large species I7- 



17. Cheeks with a large tooth below; mandibles much produced; clypeus smooth and 

 shining (Eldora, Aug. 31, fls. Gaillardia, Rohiver, Ward, fls. Senecio and Frasera) 



armaticeps Cresson 



Cheeks without such a tooth below 18. 



18. Mandibles with' a large outstanding basal process; clypeus deeply emarginate. 



(Boulder, Ward, fls. Phacelia) propinqua Cresson 



Mandibles without such a process IQ- 



19. Smaller; head and thorax strongly blue and green; base and sides of second 

 abdominal segment with short white pubescence (Boulder, June 12, W. P. Ckll.) 



senior Ckll. 

 Larger; head and thorax very dark; hair at base of second abdominal segment 

 black 20. 



20. Smaller; clypeus densely punctured (Ward, July, fls. 5e«€cto) . wardiana Ckll. 

 Very large and robust; clypeus with well-separated punctures (Boulder, fls. Carduus, 

 Ckll.; Boulder, June 22, G. HiU.) pascoensis Ckll., var. 



21. Black here should come the unknown $ of hypocrita 



Dark blue or green 22. 



22. Vertex with hair wholly pale 23. 



Vertex with hair at least partly black 25. 



23. Very small; hair of hind femora white; legs metallic; hind margins of abdominal 

 segments dark; flagellum darker than in typical proxima (Boulder, fls. Phacelia, 



June 12, 1905, W. P. Ckll.) proxima Cresson, var. 



Hair of hind femora black 24. 



24. Small, green, with small ocelli and narrow face (Boulder, June 4, W. P. Ckll.) 



wheeleri Ckll., var. 



Larger, bluer, with large ocelli (Boulder, June 4, 9 and 10, W. P. Ckll.) . 



cyaneonitens Ckll. 



25. Hair of upper part of pleura largely, but not all, black; large species (Boulder, 



May 20, Rohwer) viridior Ckll. 



Hair of upper part of pleura all black; flagellum moniliform; hind basi tarsus 

 toothed (Boulder, April 20, fls. Pulsatilla hirsuiissima and Claytonia lanceolata) 

 species agreeing with lignaria Say, but as the females of this group (Ceratostnia) 

 taken at Boulder are all propinqua, I infer that they belong to that species, the two 

 not being separable in the male. 



Hair of upper part of pleura not black 26. 



26. Larger; hair of face and thorax yellowish, the latter with long black hairs inter- 

 spersed (Boulder, April 20, fls. Pulsatilla hirsuiissima) . olivacea Ckll. 

 Smaller 27. 



27. Hair of face and thorax above white, the latter with black hairs interspersed; face 



