ODYNERUS. 309 



12. Body fulvo-velutinous ; prothorax and first 

 segment posteriorly well margined with 

 yellow ; wings ferruginous on tjie anterior 

 edge. 139. otomitus. 



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

 segment very narrowly margined, or quite 

 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 liaving 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 jiost-scutel by 

 deep fissures. 



This type establishes the passage from the true Odynerus to 

 the Stenodynerus. 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. 



112. O. spillifer Sauss. — Gracillimus, elongatus ; clypeo piriformi, 

 pnnctato, apice arcuato-truncato, biangulato. Caput, thorax et abdo- 

 minis primum segmentum, tenuiter dense punctata. Thorax couvexus, 

 antice haudcoarctatns, tenuitercristato-marginatus ; scutellis deplanatis ; 

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

 postice oblique excavato, canthis lateralibus valde acutis, utrinque 

 dentem efficientibus ; foveola strigata, rugosa ; canthis inferis acutis, 

 valvis articulationis latis ; canthis superis obsoletis, superne pone post- 

 scutellum in spinas 2 erectas elongatas excurrentibus. Abdomen sub- 

 velutinum ; primo segmento brevi, latitudine fere secundo sequali, an- 

 tice rotundato, truncato, superne per sulcum partito ; secundo elongato; 



