ODYNERUS. 309 



12. Body fulvo-velutinous ; prothoras and first 

 segment posteriorly well margined with 



yellow ; wings ferruginous on the anterior 

 edge. 139. otomitw. 



12, 12. Body argenteo-sericeus ; prothorax and 1st 

 segment very narrowly margined, orqnite 

 black; 2d segment widely margined; 

 wings cloudy. 141. Peyroti. 



11, 11. Metathorax punctate, not so rugose ; wings 

 smoky. ■ 138. huastecus. 



Description of the species. 



I. Metathorax having its posterior plate superiorly terminated 

 by two erect teeth, or by an erect crest. 



A. Metathorax not prolonged beyond the post-scuiel, but truncate 



at its apex, posteriorly excavated, angulate on each, side ; 



the superior edges of the posterior plate terminating in two 



erect spines, which are separated from the post-scutel by 



■ deep fissures. 



This type establishes the passage from the true Odynerus to 

 the Stenodyncrus. The metathorax continue to be formed as in 

 the Odynerus propr. diet., angular and sharp, but the post-scutel, 

 instead of being transversely truncate and crested, advances 

 angularly between the spines of metathorax, and is not sensibly 

 truncate. The first abdominal segment is short and truncate 

 anteriorly. The other characters are quite those of Stenodynerus : 

 Head rounded and convex; body slender, rather cylindrical, the 

 first abdominal segment more punctate than the rest of the 

 abdomen. 



1I9J. O. spinifer Sauss. — Grraoillimtis, elongatus ; clypeo piriformi, 



punctato, apice arcuato-truncato, biangnlato. Caput, thorax et abdo- 

 minis primum segmentum, tenuiter dense punctata. Thorax oonvexus, 

 antice baud coarctatns, tenuiter crista to-marginat us ; scutellis deplanatis ; 

 post-scutello trigonali, apice hand vel obsolete truncato ; metanoto 

 postiee oblique excavato, cahtbis lateral ibus valde acutis, uti 

 dentem effioientibus : foveola strigata, rugosa; oanthis infei 

 valvis artionlationis latia ; oanthis superis obsoletis, superne pone post- 

 soutellum in spinas 2 erectas elongatas exourjrentibus. Ab lom n 

 Vflutiunni ; primo segmento brevi, latitudine fore seoundo teqnali, an- 

 tice rotundato, truncato, superne per suleuin partito : seeuiulo elo] 



