Studies of North American Bees 105 



margined by reddish; a large cuneiform yellow pleural mark 



sometimes narrowly divided into two spots; 10 mm arenicola 



4. Punctures of mesoscutum strong and close but less coarse and scarcely 

 at all subcancellate, the surface between shining; flagellum 

 wholly red; supraclypeal area with a yellow spot; lateral face 

 marks broadly trapezoidal, wholly yellow ; a small round yellow 

 pleural mark ; 7 mm amorphae 



5. Apical margins of tergites 2-4 scarcely reflexed; flagellum red, 

 scarcely darker above; spot on pleura large, cuneiform; second 

 submarginal cell much narrowed above; ornaments more cream 

 color ; 7.5r-8 mm vierecki convolvuli 



5. Apical margins of tergites 2-4 broadly polished and distinctly re- 

 flexed ; flagellum red, becoming blackish above ; spot on pleura 

 small, rounded; second submarginal cell subquadrate; orna- 

 ments more yellow; 9 mm putnami 



(The female of crassiila is unknown or unrecognized.) 



Males 



Mesoscutum with the punctures very dense, more or less subcancellate ..i 



Mesoscutum with the punctures well separated, not subcancellate 5 



X. Propodeum with yellow spots modesta and modesta vegana 



I. Propodeum without yellow spots 2 



2. Yellow band on tergite 2 broad laterally but gradually much narrowed 

 medially; abdominal sternites 3 and 4 with narrowly inter- 

 rupted pale yellow lines ; 8-9 mm texana 



2. Yellow band on tergite 2 subuniformly broad, merely sharply notched 



medially on anterior margin; abdominal sternites all black ...3 



3. No supraclypeal mark ; clypeal sutures broadly black ; mesoscutum 



coarsely, cancellately punctured; 8.5-9 min crassula 



3. A distinct supraclypeal mark; clypeal sutures narrowly black ....4 



4. Punctures of mesoscutum very coarse and close, mostly subcancellate 



and causing a rugose surface ; flagellum dusky above ; lateral 



face marks barely attaining vertex ; axillae usually reddish, the 



lobes of the mesoscutellum separated by a reddish or black 



line; wings darker; 11 mm arenicola 



4. Punctures of mesoscutum strong and close but less coarse and scarcely 

 at all subcancellate ; flagellum clear red ; lateral face marks 

 more produced along orbital margin, connecting with postor- 

 bital spot; axillae and mesoscutellum j-ellow; 7 mm. . .amorphae 

 5. Spot on pleura large, cuneiform ; anterior tibiae wholly red ; ab- 

 dominal sternites 3 and 4 with yellow hues ; 6.5-7 mm- 



vierecki convolvuli 



5. Spot on pleura small ; front of anterior tibiae yellow ; venter 



wholly blackish brown ; 9 mm putnami 



105 



