98 Bulletin of the Brooklyn Entomological Society Vol. XII 



Key to the Nearctic Species. 



1. Males 2. 



Females lo. 



2. Flagellar joints four to eight produced beneath 3. 



Flagellar joints simple 6. 



3. Enclosed area of propodeum flat and uniformly longitudinally striate 4. 

 Enclosed area of propodeum depressed basally, the base with longi- 

 tudinal rugae, the apical part shining 5. 



4. Petiole slightly longer than the hind basitarsis ; head seen from above 



with anterior width distinctly less than twice the length, not nar- 

 rowing distinctly behind the eyes rileyi Fox. 



Petiole slightly shorter than the hind basitarsis ; head seen from above 

 with the anterior width nearly as great as the length, distinctly nar- 

 rowing behind the eyes errans Rohwer. 



5. Distance between the eyes at the clypeus distinctly greater than the 



length of the eye; vertex with distinct although scattered punctures, 



confertim Fox. 



Distance between the eyes at the clypeus subequal with the length of 



the eye ; vertex practically impunctate cockerelli Rohwer. 



6. Propodeal enclosure longitudinally striate; anterior margin of the cly- 



peus t'ridentate nearticus Kohl. 



Propodeal enclosure rugose; anterior margin of the clypeus arcuately 

 emarginate 7. 



7. Head seen from above with the cephalo-caudad length distinctly more 



than half the anterior width; petiole distinctly longer than hind 



basitarsis concolor Say (Fox) . 



Head seen from above with the cephalo-caudad length less than or 

 subequal with the anterior width; petiole subequal with the hind 

 basitarsis 8. 



8. Propodeum with a more or less distinct, U-shaped, finely aciculat'e ridge 



defining off the more coarsely rugose area; mesoscutum with close 

 punctures anteriorly angularis Fox. 



Propodeum without a U-shaped ridge 9. 



g. Distance between the eyes at the clypeus distinctly greater than the 

 length of the eye; scutum transversely striato-punctate ; ocellocular 

 line nearly twice as long as the postocellar line shawii Rohwer. 



Distance between the eyes at the clypeus slightly less than the length 

 of the eye; scutum shining, sparsely punctured; ocellocular line but 



little longer than the postocellar line virginiana Rohwer. 



TO. Basal dorsal area of the propodeum with distinct longitudinal carinas 11. 



Basal dorsal area of propodeum rugoso-reticulate 13. 



II. Anterior margin of the clypeus strongly biemarginate or tridentate; 

 scutum shining, sparsely punctured nearcticus Kohl (Fox). 



Anterior margin of clypeus not biemarginate; scutum transversely 

 rugulose ; . . . 12. 



