250 UNIVERSITY OF COLORADO STUDIES 



Lateral face-marks not extending above level of antennae 6. 



6. Larger; yellow on clypeus interrupted in middle (Boulder, fls. Grindelia, Aug. 7, 



W. P. cm.) porterse Ckll. 



Smaller; yellow on clypeus not interrupted in middle ; upper part of clypeus with a 

 large W-like black mark; sixth abdominal segment bright lemon-yellow (Boulder, 

 June, G. Hite) blanditxun praedentatiun Ckll. 



7. Smaller; scutellum all dark tenuiflorae Ckll. 



Larger; scutellum at least with yeUow dots 8. 



8. Lateral face-marks extending above level of antennae; large species; abdominal 



bands not interrupted in middle occidentale Cresson 



Lateral face-marks not extending above level of antennae 9. 



9. Ground color of abdomen a more or less lively red; last segment red (Boulder, 



fls. Psoralea, Aug. 8, W. P. Ckll.) porterse amabile Ckll. 



Ground color of abdomen dark 10. 



10. Apical segment red; size large porterae Ckll. 



Apical segment black 11. 



11. Abdomen spotted, though some of the spots are united by lines; axillae with light 



spots porterae personulatum Ckll. 



Abdomen banded, though the bands are partly interrupted; axillae without light 

 spots 12. 



12. Markings of abdomen light yellow emarginatum (Say) 



Markings of abdomen deep chrome yellow (Fort Collins) . . titusi Ckll.* 



DIANTHIDIUM CockereU 



Females i. 



Males 4. 



1. Legs red 2. 



Legs yellow and black, or black with yellow marks 3. 



2. Smaller; clypeus all black; scopa white (Boulder, fls. Psoralea, Aug. 8, W. P. Ckll.) 



concinnum (Cresson) var. 

 Larger; clypeus light at sides (Boulder, fls. sunflower, Aug. 8, W. P. Ckll.) 



sayi Ckll. 



3. Abdominal markings deep yellow; clypeus light at sides (Boulder, nesting in hole 

 in brick wall at Kruger's house, Aug 2. Ckll., South Boulder Canyon, fls. Grindelia, 



Aug. 9, W. H. Ckll.) parvtim (Cresson) 



Abdominal markings very pale yellow (Boulder, September, S. A. Rohwer) 



pudiciun (Cresson) 



4. Legs red (Boulder, fls. Grindelia, Aug. 7, W. P. Ckll.) sayi Ckll. {interruptum Say) 

 Legs yellow and black (Boulder, fls. Grindelia, Sept. 3, Ckll., fls. Grindelia and 

 Chrysothamnus, Sept., Rohwer; S. Boulder Canyon, fls. Grindelia, Aug. 9) 



parvum (Cresson) 



OSMIA Panzer 



Females i. 



Males 21. 



I. Black without any metallic colors; looks Uke Monumetha, but eyes diverging above; 



