ODYNERUS. 181 



regular yellow border. Legs black, varied often with ferruginous. 

 Wings ferruginous with the end gray. 



Var. The. yellow passing into ferruginous and the ferruginous 

 into yellow. 



Bess. a. diff. — This species wonderfully resembles those which 

 form the group of the 0. nasidens, but it is sufficiently distinct 

 from it in the presence of the suture of the first segment of the 

 abdomen. It is also more slender. 



Hub. The temperate climes of Mexico. Valley of the Mex- 

 tillan. 4 ?. 



b. Abdomen more ovalo-conical ; the border of the 2d segment rugose or . 

 reflexed. 

 (Section I, b, Saussure Vespides, I, 139.) 

 Group of the Odynerus unifasciatus. 

 24. A. unifasciatus Sauss. — Gracilis, niger, cribri instar punctatus ; 

 abdominis secundi segmenti margine canaliculate), subreflexo, perru- 

 goso ; antennis subtus ferrugineis ; puncto frontali et post-oeulaii, macula 

 biloba pronoti, post-scutelloet abdominis primi segnienti margine, flavis. 

 — ?• Clypeoflavo-bi punctata. — % . Clypeo, maudibulis et abd. secundi 

 segmenti, limbo, flavis. 

 Variat. £ secundo % tertio et quarto abd. segmento flavo-limbato. 



Odynerus uncinates 1 Say, Boston Journ., I, 1S37, 286, 4. Say's Entom. 



(Le Conte), II, 7(50, 4. 

 Odynerus unifasciatus Sauss. Vespides, I, 138, 21 ; III, 205. 



J . Total length, 14-15 mm. ; wing, 11 mm. 

 % . Total length, 11 mm. ; wing, 8. 



9. Form slender. Head and thorax cribrosc with great 

 separated punctures. Clypeus convex, strongly punctured, widely 

 pyriform, terminated by two very small, near together and diverg- 

 ing teeth. Head strongly and densely punctured. Thorax quite 

 lengthened, a little retracted posteriorly, everywhere strongly 

 cribrose with foraminiform punctures. Prothorax finely bordered, 

 without angles. Mesothorax presenting two grooves on its hinder 

 part. Metathorax very rugose above, reticulately shagreened, 

 corrugated; its concavity quite flat, indistinctly striate and 

 punctate, without spines on the sides, superiorly bordered by an 



1 It is evidently not the 0. unifasciatus which Fabricius described 

 under the name of Vespa uncinata, which is rather the Monobia A-dens, 

 because he says that all its markings are snowy-white, and that the size 

 is that of the Vespa macidata. 



