244 UNIVERSITY OF COLORADO STUDIES 



DIAWDRENA CockereU 

 Similar to Andrena, but with only two submarginal cells. 



Male 8 mm. long, olive-green; legs, antennae and mandibles black; female just 

 over 9 mm. long, olive-green to bluish-green (Boulder, in May) nothocalaidis Ckll. 



ANDRENA Fabricius 



Females i. 



Males 25. 



1 . Thorax and first four segments of abdomen above covered with bright fox-red hair 



(Boulder, G. Hite) hitei CkU. 



Not so . 2. 



2. Tegument of abdomen red, more or less marked with black ... 3. 

 Tegument of abdomen not red 4- 



3. Pubescence fulvous; basal joints of antennae more or less strongly ferruginous 



(Boulder, fls. Pulsatilla, May 2, Maru Gill) pninorum Ckll. 



Pubescence usually paler; antennae entirely dark (Boulder, fls. Pulsatilla and 

 Odostemon) prunorum gillettei Ckll. 



4. Black, with entirely black hair (Boulder, fls. Ribes) .... porterae Ckll. 

 At least some of the hair not black 5' 



5. Abdomen with a decided metallic (greenish or bluish) tint; rather small species, 

 about 9 mm. long, with rather weak white hair-bands on abdomen ... 6. 

 Abdomen not metallic ?• 



6. Stigma amber-color or ferruginous (Boulder, fls. Salix, H. House and Ckll., also 



fls. Odostemon) Candida Smith. 



Stigma dark (Boulder, fls. Hydrophyllum, May 22, CkU.) geranii Robertson 



7. Hind tarsi clear-red; hind tibiae largely or wholly red .... 8. 

 Hind tarsi and tibiae (excluding the hair) brown or black . 10. 



8. Thorax above covered with fulvous hair; insect 8 mm. long (Boulder, June 4) 



wilmattse Ckll. 

 Thorax above with whitish hair 9- 



9. Larger; punctures of mesothorax small and rather feeble (Boulder, fls. Cratagus 

 Colorado Ashe=C. coloradensis Nelson,' May 20) . . . claytoniSB Robertson 

 Smaller; punctures of mesothorax exceedingly large and deep (Boulder, June, 

 W. P. Ckll.) perforatella Ckll. 



10. Hair of face and pleura black ii- 



Hair of face wholly or mainly pale 12. 



11. Larger, about II mm. long; hair of thorax above fox-red; abdomen shining black, 



without bands (Boulder and Gregory Canyon, fls. Odostemon, April) 



berberidis Ckll. 



Smaller, about 8 mm. long; hair of thorax above brown; abdomen with feeble 

 hair-bands (Boulder, fls. Pulsatilla hirsutissima, April 19, Marie Gill) 



mgrihirta (Ashmead) 



12. Very small species, about or little over 6 mm. long 13. 



Much larger I4- 



13. Flagellum bright red beneath (Boulder, fls. Salix) .... salicinella Ckll. 

 ' Cratagus Colorado has cream-colored anthers; those of C. ouidentalis are pink. 



