ODYNERUS. 301 



Division STENODYNERUS. 



(Sauss. Vespides I, Divis. IV, 206.— Ill, Divis. Epsilon, 11° Sect., p. 255. 

 Stenodynerus, Melang. Hymenopt. II fasc, p. 58.) 



Body elongate, generally slender ; often cylindrical. Abdomen 

 slender and cylindrical, or ovate, not quite sessile, or spindle- 

 shaped, subpedunculate. Its first segment variable, having 

 the shape of rather an elongate bell, rounded anteriorly or 

 cup-shaped, subpedunculate, or funnel-shaped, often longer 

 than wide. — Post-scutel generally entire, not truncate, 

 angular posteriorly ; but yet sometimes truncate when the 

 abdomen is spindle-shaped and subpedunculate. 



This is a type very richly represented in America. 



The Odyneri of this division constitute a special type, remark- 

 able by the elongation of their forms, which is among the Odyneri, 

 quite a corresponding similarity between the Slenancistrocerus 

 and the Ancistrocerus. 



The parallelism is so complete that one may even designate in 

 both groups some corresponding species of which some are quite 

 approximate, merely differing by the presence or absence of a 

 suture on the 1st abdominal segment, 1 others very analogous, 2 

 although not quite so similar. This very difficult group is not 

 distinguished by any one special character, but by the combina- 

 tion of several, which are not all general to all the species, each 

 species uniting only a certain portion of them, which partly occur 

 in other Odyneri, but are combined in other ways. This makes 

 the Slenodyneri very difficult to recognize, for one not very 

 familiar with the genus Odynerus. 



1 0. conformis. A.fulvipes. 



n f A. scccularis. 



(J. vagus. < 



*- A. Bravo. 



2 a. Abdomen elongate, cylindrical. 



0. Enyo. A. histrio. 



O. lotonacus. A. Mexicanus. 



b. Abdomen more ovate, 1st segment cup-shaped. 

 0. speciosus. A. militaris. 



0. Peyroti. A. Sumichrasti. 



c. Metathora.r produced posteriorly ; wings black, ornaments white. 

 0. luctuosus. A. quadrisectus, etc. 



