3(J HYMENOPTEEA OF AMERICA. [PART I. 



post-scute! and by its square, angled, not contracted prothorax; 

 by its metathorax and petiole, etc. The very coarse punctation 

 ami very particular details of form of all the parts of the body 

 distinguish this species from all the other Mexican Zethus, except 

 from Olmecus with which it must be compared. 

 Hab. Mexico. The Oriental Cordillera, Orizaba. 



22. Z. Aztecus Sauss. (Fig. 1, hi.) — Ittger, rngose puuetatus ; pronoto 

 antice valde cristato; fronte transversim in lineam elevato, flavo- 

 bipnnctato; netiolo ovato-inrlato, crasse punctato ; secundo segmento 

 Bubpetiolato, fulvo-sericeo ; pronoti margine, macula subalari, scutelli 

 m iculia -, post-scutelli fascia abdominisque segwentoruui 1-3 liuibo, 

 flavis; alis subhyalinis. 



aztecus Sa0ss. Revue Zool. IX, 1857, 270. 



Total leugth, 15 iuui. ; wiug, 10 mm. 



2. Head, thorax ami petiole cribrose with coarse crowded 

 punctures, but less rough than with Z. cristatus and Z. spinosus. 

 Clypeus polished, cribrose with mure distant oblique punctures, 

 and hardly notched on its inferior border; the emargination 

 divided by a little middle tooth; a little wavy transverse carina 

 mi the vertex, forming a sort of extension upon the insertion of 

 the antennae. Clypeus and orbicles rather silvery. Prothorax 

 bordered by a vertical lamina in form of a crest, but 'which does 

 nol prolong itself upon the sides. Metathorax furrowed, with the 

 concavity bordered above ami furnished with a pile of gray hairs, 

 having a slight tawny reflection. Post-scutel unarmed. Swelling 

 of the petiole neither cylindrical nor globular, but oval, and, as 

 seen in profile, dilated above. Second segment ovate-globular, 

 not enlarging itself as suddenly as in the Z. <-ri.<ittht* ; but it has 

 no more length of pedicle, and the same silky, golden reflection. 



[nseel black; two dots on the forehead, border of prothorax, 

 a spol under the win-', two on the scutel, the post-scutel, and the 

 border of segments 1. 2, :; orange-yellow. Wing-scales often 

 touched with yellow. These colors offer the same variation as in 

 the specil S cited; the eiv-t of the vertex being often adorned with 

 a yellow line, while the metathorax has no spots of this color. 1 



1 Al I i>ast in my specimens. It will not do, bowever, to accept this as 

 a constant character. 



