ODYNERUS. 359 



Var. The yellow band of scute! interrupted. 



9. Ilead and antennas quite blaek. Clypeus cribro.se like the 

 head ; having the shape of a square lozenge, its inferior margin 

 arcuate, imperceptibly bidentate. 



Bess. a. diff. — This species has much resemblance to 0. Tacu- 

 baym, because of its elongate 2d abd. segment, but it is quite 

 distinct from it, as also from 0. coyolus and totonacus, by its 

 truncate, crested post-scut el, and its bidentate metalhorax. This 

 last character only separates 0. tepanecus, olmecus, and nahuus. 

 llab. The temperate parts of Mexico. 1 caught one ? in the 

 valley of Mextitlan. 



154. O. tepanecilS Sadss. — Parvulus, gracilis, niger, tenuiter punc- 

 tatus ; post-scutello truncato ; metathorace valde bituberculato ; abdo- 

 minis l°segmento infundibuliformi, subpetiolato; apicepuncto impresso 

 notato, capitis punctis, pronoti, scutelli, abdominisque seguaentorum 1', 

 2 1 (vel V, 2', 4'), margiue, flavis ; tibiis basi flavo-variis. — $. Clypeo 

 flavo, apice spinis 2 nigris, antennis nigris. 



Odyn. Tepanecus Sadss. Revue de Zool., IX, 1857, 280, % 



2- Total length, 7.5 mm. ; wing, 5.5 mm. 



Very small. General form very much as in 0. acolhuus, 

 slender. Head circular or a little higher than wide. Antennae 

 inserted rather low. Notch of the eyes very open. Prothorax 

 not having its angles dentiform. Scutel truncate, transverse, not 

 crested, but having a transverse edge. Metathorax triangular, 

 a little prolonged; its lateral edges arcuate, sharp, hairy; its 

 hinder face parted by a deep channel and armed on each side 

 under the angles of post-scutel with a strong, sharp, dentiform 

 tubercle, looking backward; these tubercles compressed, having 

 a sharp, lateral salient ridge, extending to the angles of post-scutel 

 (very evident, when viewed in profile). Apex of metathorax with 

 two wide articulate, not spined valvse. Abdomen slender, spindle- 

 shaped; first segment small and narrow, subpetiolate, funnel- 

 shaped, but swelled above, gibbous, as if truncate anteriorly; au 

 impressed point before its posterior margin. Second segment 

 rather oval, nan-owed but not constricted at base, rather depressed, 

 but not all tubereulate. The whole insect finely punctured. 



Black, sericeous. A frontal, ocular, and post-ocular spot, 



yellow. Anterior margin oi° prothorax, posterior margin of 



scutel, articular valvaj o( the metathorax, and the first two Beg- 



