258 UNIVERSITY OF COLORADO STUDIES 



Scutellum with yellow or fulvoxis hair 7. 



7. No black band between the wings 8. 



A distinct black band between the wings 12. 



8. Abdomen black with first and part of second segment yellow-haired (Boulder, 



fls. sunflower, Aug. 9, W. P. Ckll.) separatus Cresson 



Abdomen with the yellow covering first two segments, and at least part of third 



9- 



9. Lower edge of yellow strongly convex; large species (Boulder, /. Henderson, 



May II, Rohwer) morrisoni Cresson 



Lower edge of yellow straight 10. 



10. Face very narrow; apex of abdomen with reddish hair 



nevadensis Cresson $ (Jmprobus Cr.) 

 Face normal ; females ii. 



11. Abdomen vsdth first three segments yellow (near S. Boulder Creek, about 7 miles 

 from Boulder, Youngblood, Boulder, August, W. P. Ckll.) . nevadensis Cresson 

 Abdomen with the first four segments yellow (Boulder, fls. Helianthus, Aug., 



Rohwer) dorsalis Cresson 



(The male of dorsalis has the abdomen yellow-haired, with only the last segment 

 and the sides of the penultimate black-haired.) 



12. Thorax before the band white-haired; abdomen with the hair tawny, and no black 

 band (Boulder, Ckll., Arapahoe Peak, above timber-line, Aug. 31, W. P. Ckll.) 



apposittis Cresson 

 Thorax before the band yellow or tawny-haired 13. 



13. Abdomen with the first four segments yellow-haired 14. 



Abdomen with the basal half at least mainly black-haired ... 15. 



14. Yellow of abdomen suffused with red, especially at sides; hair of face pale (Boulder, 



W. P. Ckll.) rufosuffusus Ckll. 



Yellow of abdomen not suffused with red; hair of face black (Boulder, G. Weston, 

 fls. stmflower, Aug. 6 and 7, W. P. Ckll.) fervidus Fabricius 



15. Apex of abdomen with pale hair; hair of base black 16. 



Apex of abdomen with coarse black hair, but yellow at sides of fifth segment; 

 hair of first and part of second segment pale 17« 



16. First two and fourth segments black, apex white (Boulder, May, Rohwer) 



prozimus Cresson 

 First two segments black, third yellow or tawny, fourth to sixth white (Boulder, 

 fls. Prunus, May, Chas. Sellers) proiimus coloradensis Titus 



17. The broad black band of abdomen with coppery-red hairs intermixed (Eldora, 

 fls. Gaillardia, Aug. 31, Rohwer) .... rufocinctus iridis (Ckll. & Porter) 

 The band entirely black; appearance of B. edwartisi* (Boulder, Ward; fls. Astra- 

 galus, Phacelia) rufocinctus astragali Ckll. 



APIS L. (domesticated) 



Abdomen dark (Boulder) mellifera L. 



Abdomen very largely rufo-fulvous (Boulder, fls. Pulsatilla, etc.) 



mellifera ligustica Spinola. 



