74 AMERICAN HYMENOPTEKA. 



10. CoxEe, trochanters and femora clothed to a considerable extent with 



ferruginous pile riibicuiidus. 



Coxee, trochanters and femora with little or no ferruginous pile..ll. 



11. Dorsum of abdomen with the first five segments clothed with red- 



dish-ferruginous, or orange pile 12. 



Dorsum of abdomen not having all the first five segments clothed 

 with reddish-ferruginous pile 13. 



12. Occiput with a conspicuous triangle of reddish-ferruginous or 



orange pile; mesopleura bicolored ; epipygium black. 



dalilboiuii. 

 Occiput black ; mesopleura unicolorous; epipygium reddish-ferru- 

 ginous baeri. 



13. Mesopleura black or dark cinereous 14. 



Mesopleura yellow 19- 



14. Second dorsal abdominal segment reddish-ferruginous 15. 



Second dorsal abdominal segment entirely or mostly black 17. 



15. First dorsal abdominal segment black 16. 



First dorsal abdominal segment clothed with ferruginous pile. 



biitteli. 



16. Malar space more than one-third as long as the eye....caroliiius. 

 Malar space less than one-third as long as the eye cocciueus. 



17. Dorsum of thorax black -IS- 



Dorsum of thorax yellow or reddish emilite. 



18. Malar space slightly longer than its width at apex. 



clolichocephalus. 



Malar space distinctly shorter than its width at apex. 



bi'achycephalus. 



19. The second and third dorsal abdominal segments bearing more or 



less reddish pile on the sides ; the apical segments entirely 



black piilcher. 



Neither the second nor the third dorsal abdominal segment with 

 reddish pile ; the epipygium thinly sprinkled with pale fer- 

 ruginous hairs moiitezunise and weisi. 



20. First dorsal abdominal segment entirely black crotcliii. 



First dorsal abdominal segment clothed with yellow pile 22. 



21. Dorsum of thorax yellow, with a black interalar band. 



robustus var. hortulaiis. 

 Dorsum of thorax unicolorous voliicelloides. 



22. Third dorsal abdominal segment red-ferruginous 23. 



Third dorsal abdominal segment black 24. 



Third dorsal abdominal segment yellow 25. 



23. The two apical dorsal abdominal segments red-ferruginous. 



haueri. 

 The two apical dorsal abdominal segments black 26. 



