NORTH AMERICAN BEES. 237 



6. Scutelluin, and a broad band down middle of cly- 



peus, yellow .... mexicana, vigilans, trepanda. 

 Scutellum not at all yellow ..... 7. 



7. Lateral face-marks shaped like feet on tiptoe . asinina. 

 Lateral face-marks verv narrow, not like feet 



Sp. from Tuerto Mt., N.M. 

 Lateral face-marks triangular . . . Sp. from Texas. 



8. Small species, with the punctuation of the pleura 



sparse and shallow ...... 8a. 



Mostly larger species, face-marks triangular or bow- 

 shaped, pleura coarsely punctured ... 9. 

 8a. Clypeus with a light spot, face-marks subtriangular, 



tegulae with a yellow spot ..... mesillce. 



Clypeus all dark, face-marks bow-shaped, tegulae 

 all dark, collar dark .... pygmcsa, S. Dakota. 



Clypeus all dark, face-marks narrowly triangular, 

 tegulae with a yellow spot, collar dark pygmaa, var., Colorado. 

 (There may be a little spot on clypeus of pt/ymaa.) 



9. Lateral face -marks triangular . . . . 10. 

 Lateral face-marks elongate or bow-shaped . . 12. 



10. Lateral face-marks curved inward at the apex, 



tegulae all dark (rarely with a spot) . . . modesta. 

 Similar, but much more sparsely punctured . . sparsa. 

 Similar, but thorax much more coarsely punctured, 



wings darkened ....... confluens. 



Lateral face-marks terminating in a point on orbital 



margin . . . . . . . .11. 



11. Somewhat larger, tegulae without a yellow spot . 11a. 

 Somewhat smaller, tegulae with a yellow spot . lib. 



11a. Face-marks pure white .... Sp. from Texas. 



Face-marks deep yellow . . . . .lie. 



lie. Wings hyaline, 2nd submarginal cell longer 



ivootoni (presumably). 

 Wings subfuliginous, 2nd submarginal cell shorter. 

 (The 2nd submarginal varies, however ; the 

 tegulae may have a small yellow spot) . Sp. from Georgia. 



116. Clypeus all dark ....... zizice. 



Clypeus with a very broad pale band, or conical 

 mark ........ lid. 



lid. Thorax closely and finely punctured, scutellum 

 closely punctured, wings pale fuliginous, band on 

 clypeus .... Sp. from California (baker i ?). 



Thorax coarsely and deeply punctured, scutellum 

 sparsely punctured, wings hyaline, conical mark 

 on clypeus ........ azteca. 



12. Wings fuliginous, no spot on tegulae . . . schwarzii. 

 Wings hyaline, no spot on tegulse (rarely a small 



spot) ......... 12a, 



Similar, but much smaller . . . Sp. from Georgia. 

 Wings hyaline, a spot on tegulae .... 126. 



Similar, wings fusco-hyaline, markings cream-colour 



limbifrons. (Cuba.) 



