AMERICAN HYMENOPTERA. 109 



4. Third and fourth antennal joints equal; fifth joint not shorter 



than the fourth. (Colorado.) fosser Roh. 



Third antennal joint distinctly longer than fourth; fifth joint 

 shorter than fourth. (Kansas.) foxii Vier. 



5. Mandibles black 6. 



Mandibles yellowish 7 . 



6. Pronotum short, carinated anteriorly, with two white spots. 



(U. S. east of Rockies.) plenoculoid.es Fox. 



Pronotum longer, rounded anteriorly, black. (Colorado.) 



niger Roh. 



7. Submedian cell shorter than the median; posterior tibiae black. 



(Colorado) sayi Roh. 



Submedian and median cells equal or nearly so, if not, then the 

 submedian is longer; posterior tibia? black, with a white 

 stripe 8. 



8. Four anterior femora and all the tibia? beneath yellowish. (Texas.) 



iiierinis Cress. 

 Four anterior femora with only a yellow spot beneath, four an- 

 terior tibia? all black; first recurrent nerv. farther basal of 

 first tran. cu affinis Roh. 



9. Postscutellum yellow or creamy 10. 



Postscutellum black 11. 



10. Furrow from the anterior ocellus not extending to near the ver- 



tex; head shining, the punctures more separated; emargi- 

 nation of the eighth ventral plate broad. (Colorado) . 



lucidus Roh. 



No furrow from anterior ocellus to the vertex; head dull and 



closely punctured ; emargination of the eighth ventral 



plate narrow. (Texas.) inermis Cress. 



11. Mandibles black 12. 



Mandibles yellowish 13. 



12. Submedian cell distinctly longer than the median; abdomen red. 



fossor Roh. 

 Submedian and median cells equal or nearly so; abdomen black.. 13. 



13. Pronotum short, sharply truncate anteriorly; clypeus without a 



median tooth plenoculoides Fox. 



Pronotum longer rounded anteriorly; clypeus with a median 

 tooth 14. 



14. Clypeus with a small acute median tooth; first recurrent nervure 



free from the first tran. cu uiger Roh. 



Clypeus with a broad obtuse median tooth; first recurrent nerv- 

 ure interstitial with the first tran. cu modest us Roh. 



15. Submedian cell distinctly shorter than the median; pronotum 



black sayi Roh. 



TRANS. AM. ENT. SOC, XXXV. MARCH, 1909. 



