ODYNERUS. 207 



Mexican var. (See the description of those species.) In coiois 

 it wholly resembles the Ancistrocerus tuberculiceps. 



It has a greater relation in form to the 0. arvensis, but it is a 

 little larger, and it differs from it by the border of the 2d segment, 

 which is not only depressed, but very subcanaliculate ; and by 

 the elypeus % which is entire, not bidentate, but rather rounded 

 on its anterior border. 



Finally, it differs from the 0. dorsalis % by its wings, which 

 are not violet; by the border of the 2d segment, which is not as 

 distinctly reflexed as in the 0. dorsalis, and by the summit of 

 the inetathorax, which does not offer post-scutellar crenulate 

 eminences. The palpi arc also a little more slender. 



Bab. The hot parts of Mexico. I have taken 4 % of this 

 species in the valley of Mextitlan, and the var. in Cordova. 



$)©. O. Mclems Sauss. (Fig. 14, 14«.) — Validus, niger, nitidus ; rceta- 

 noto postice late excavato, acute inarginato, bidentato ; clypeo 9 £> 

 apice truncate-, haud bidentato ; abdornine conico, sparse puuetato, 

 margine seginentorum 2 i -5 i densius punctato ; pronoti et raetanoti rnacu- 

 lis 2, post-scutello abdominisque primo segmento superne, albidis ; alii 

 fusco-cyaneis. 



% . Clypeo albido, puncto mandibularura, scapi et frontis, raaculisque 2 

 transversis in secundi abdominis segaieuti basi, albidis ; pedibus albido- 

 variis. 



Othjn. bidens Sadss. Rev. de Zool. XXII, 1S70, 58, 12. 

 Total length, 20 mm. ; wing, 17 mm. 



9. A large species. Clypcus covered with separated points; 

 its extremity abruptly truncate, not bidentate, and without 

 depression. Head large, swelled at the vertex, shining, and 

 covered with separated punctures. Thorax long, square, shin- 

 ing, finely punctured; prothorax hardly reflexed, not angulate, 

 slightly retracted before; mesothorax marked with four grooves; 

 post-scutel bent, transverse, joining in the truncation of the meta- 

 thorax, but not crenulate. Metathorax presenting a groat striate 

 concavity, which occupies the whole width, bounded by very 

 sharp ridges, which are separated from the post-scutel by a groove, 

 and form on each side a dentiform lateral angle. Abdomen quito 

 conical, the lirsi segment wide, truncate before; the 2d quite long; 

 its border carrying a wide, not very strong band o( punctures; 

 this band not channelled, but fiat, as if planed; following 

 incuts punctured, with a. similar band. 



