1903.] NATURAL SCIENCES OF PHILADELPHIA. 595 



T.OM-er anterior orbits not yellowish; mesothorax with not more 

 than one stripe, 6. 



6. T.arger; 10 mm. long or over; red of abdomen quite bright, 



hella, Cress. 

 Smaller; 8 or 9 mm. long 7. 



7. Red of abdomen dark, cuneata (Rob.). 



Red of abdomen light (Colorado), schwarzi, Ckll. 



8. Length over 10 mm. ; abdomen rather long, 9. 



Length under 10 mm., \q^ 



9. General color darker (Pa., N. IL), .... hella, Cress., van 

 General color lighter (Wash., Ore., B. C). . . hella, Cress., var. 



10. Dark species; scape in front black or l)]ackish, with red basal spot, 



verplexa, Cress. 

 Scape in from red 11. 



11. Two submarginal cells yrayi castonensis, Ckll., var. 



Three submarginal cells, 12. 



12. Yellow spots on second aljdominal segment small and inconspicu- 



ous, ]3 



Yellow spots on second abdominal segment conspicuous, . . 16. 



13. Face very broad; orbits hardly converging below; third submar- 



ginal cell very high and narrow, but not much narrowed to mar- 

 ginal (Wash.), wnshinqtoni, Ckll. 



Face narrower; orbits conspicuously converging below, . . 14. 



14. Third submarginal cell narrowed nearly or cjuite to a point above, 



broad below (Wash.), (jrayi eastonensis, Ckll. 



Third submarginal cell not thus narrowed above 15. 



15. Abdomen long, light red; only a little black at base of first seg- 



ment, c/myi, Ckll. 



Abdomen shorter, broader and darker; much more black at base 

 of first segment (Oregon), rJiodomelas, CkW.'! 



16. Smaller and lighter (North Carolina), .... carolirue, Ckll. 

 Larger and darker (N. H., Pa.. Lid., Ivans., Neb.), cuneata (Ro.b.). 



Males. 



1. Scutellum usually spotted with yellow; tegulse more or less yel- 



low, 2. 



Scutellum black or red; tegukie ferruginous, 3. 



2. Middle joints of antennae not longer than wide, . . ovata (Rob.). 

 Middle joints of antennje longer than wide (Texas), lepida. Cress. 



3. Clypeus with only the anterior margin yellow, though often 



broadly, 4. 



Clypeus all or with the greater part yellow 7. 



4. Abdomen broad, very dark red, with two widely distant spots on 



second segment, and usually on third. . . '. perplexa, Cress. 

 Abdomen lighter, 5. 



5. Second submarginal cell receiving recurrent nervure beyond its 



middle; al:)domen light red with four large yellow spots; scape 

 black in front; second submarginal cell narrow (Oregon), 



rhodomelas, Ckll. 



