ANALYTICAL TABLE. XXXI 



C. Only the first two abdominal segments margined 

 with yellow. (The 3d and 4th sometimes 

 indistinctly marginate.) ; 240 



2d Section. — Form more lengthened ; thorax length- 

 ened square or retracted behind. Abdomen 

 less conic, more cylindrical or depressed . 244 



a. All the segments of the abdomen, except the 



first, bordered with yellow . . . 244 



b. Abdomen varied with black and rufous . 245 

 Division Odynerus . ....... 247 



Table to assist in distinguishing the Division Odynerus 



and Stenodynerus, with regard to Pachodynerus . 247 

 Table to assist the determination of the species of Divi- 

 sion Odynerus ....... 249 



Section I. — Post-scutel sharply truncate; its trans- 

 verse edge often crenulate. Abdomen conical 

 or ovate-conical; the second segment not 

 strangulated at base ; the first segment in- 

 cluding it very naturally .... 252 



1. Posterior plate of metathorax angulate, forming 



on each side a lateral dentiform angle . 252 

 A. Concavity of the metathorax polygonal, mar- 

 gined with straight or arcuate ridges, 

 which form at their meeting a sharp angle. 

 The superior lateral edges superiorly ter- 

 minating in a tooth or eminence, sepa- 

 rated from the post-scutel by a deep 

 fissure, or by a notch .... 252 



a. Ridges of the metathorax very salient; its 



posterior face excavated . . . 252 



* Posterior margin of 2d and 3d abdominal 



segments reflexed .... 252 

 ** Posterior margin of 2d and 3d abdominal 

 segments not reflexed, but 'impressed 

 and rough ...... 255 



b. The hinder face of metathorax more flat- 



tened ; its superior edges not so salient 262 



* The superior ridges forming two elevated 



spines behind the post-scutel . . 262 

 ** The superior edges of metathorax very 

 slight, only forming behind the post- 

 scutel two very small teeth . . 264 



