36 HYMENOPTERA OF AMERICA. [PART I. 



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

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

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

 distinguish this species from all the other Mexican ZeLhus, except 

 from Olmecus with which it must be compared. 

 Hob. Mexico. The Oriental Cordillera, Orizaba. 



22. Z. AztecUS Sauss. (Fig. 1, 1«.) — ^iger, rugose punctatus ; pronoto 

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

 bipunctato ; petiolo ovato-inflato, crasse punctato ; secundo se<:mento 

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

 niaculis 2, post-scutelli fascia abdoininisque segmeutorum 1-3 limbo, 

 flavis ; alis subhyalinis. 



Zetlius aztccus Sadss. Revue Zool. IX, 1857, 270. 



Total leugtb, 15 mm. ; wing, 10 mm. 



9. Head, thorax and petiole cribrose with coarse crowded 

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

 Clvpeus polished, cribrose with more distant oblique punctures, 

 and hardly notched on its inferior border; the emargination 

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

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

 the antennae. Clvpeus and orbicles rather silvery. Prothorax 

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

 not prolong itself upon the sides. Metathorax furrowed, with the 

 concavity bordered above and 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. cristatus; but it has 

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



Insect black ; two dots on the forehead, border of prothorax, 

 a spot under the wing, two on the scutel, the post-scutel, and the 

 border of segments 1, 2, 3 orange-yellow. Wing-scales often 

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

 the species cited; the crest of the vertex being often adorned with 

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



1 At least in my specimens. It will not do, however, to accept this as 

 a constant character. 





