ZETHUS. 29 



extremity, but without angles, delicately punctured-strigate. 

 Clypeus, mandibles, and the under part of the head, yellow. 



Bess. a. diff. — This species has just the same form of head and 

 clypeus and just the same system of coloration as Z. olmecus ; 

 the petiole is also the same, but the thorax, lengthened, flattened, 

 very delicately punctured, the metathorax less excavated, with 

 not so salient carinas, make it easy to distinguish. The middle 

 carina? of metathorax stop before reaching the lateral carina?. 

 The appearance of the insect is quite different, and it looks more 

 like a Disccelius (D. zonalis) than like a Zethus ; and this 

 appearance, due to the elongate thorax, distinguishes it also from 

 Z. miniatus and lobulatus. 



Hab. Mexico. Oriental Cordillera (Mr. Sumichrast). 



B. Antennae of the males terminated by a hook. 



^ 

 a. Species having the appearance of the true Zethus. Head ivider than high; 

 thorax short, not be/in/ one and a half times longer than wide; dilata- 

 tion of the petiole elliptical or cylindrical, a little contracted behind; the 

 second segment of the abdomen inform of a globular bell. 



IS. Z. spisiipes Say. — Medius, niger, nitidus, densissime et grosse 

 eribrato-punctatus ; punctis 2 frontalibus flavis ; elypeo lato, 9 nigro, 

 subbidentato, rugose cribrato ; £ punctato, albido, surpra nigro ; antennis 

 9 atris, % linea in scapo albido; abdominis secuudo segmento minus 

 couspicue punctato, subpedunculatp; petioloinflato, campanulato, grosse 

 punctato, apice flavo-marginato. — Variat 9 % pronoto, lateribus, scu- 

 tellis, albido variegatis et abdominis secundo segmento margine albido. 



Zethus spinipes Say, Bost. Journ. I, 1837, 387, 9- — Saoss. Vespides, III, 

 122, 10. 



Eumenes substricta Hald.! Proc. Acad. Pbila. II, 1844, 54. — Sauss. Ves- 

 pides, III, 152, 42. 



Zethus variegatus ] Sacss. Vespides, I, 13, 9, J , 1852 ; Revue Zool. X, 

 1858, 66. 



Eumenes pens ylvanica Hald. Proc. Acad. Pbila. 1853, 365, % . 



Zethus bicolor Sauss. Vespides, I, 17, 1(3, % . 



9 . Insect of medium size ; ocelli disposed in a wide triangle. 

 Clypeus having the form of a transverse lozenge, twice as wide 

 as long ; having the lateral extremities very sharp, and its ante- 



' The collection, with bad locality marks, of M. de Romand, has i'ed me 

 into very many errors. 



