90 HYMENOPTERA OF AMERICA. [PART I. 



each side ; hook of the antennte ferruginous. Mandibles short, 

 but triangular, acute, with four little teeth. 



1;> ss. a. diff. — This insect, although having quite the general 

 appearance of an Eumenes, approaches DiacceUus in the form of 

 its mandibles, short and widened towards the tip in the female. 

 But it is very easy to confound it with E. mejeicanus and calli- 

 morpha. It differs by its rather convex elypeus. not so bidentate, 

 by the absence of frontal carina, by its head transverse-oval, not 

 oval-triangular, because of the great enlargement of the under 

 part of the eyes, which is wider transversely than longitudinally, 

 and by its shagreened abdomen. The exceptional form of the 

 mandibles, truncate and rounded at the end, with the external 

 side very arcuate, as also the particular form of petiole, will dis- 

 tinguish this species from all its neighbors. 



This is quite an exceptional type, remarkable by the unequal 

 form of mandibles in both sexes. 



Bab. Mexico. The Oriental Cordillera. Cordova. 2?,U. 



b. Mandibles more elongate, not truncate, rather hooked at tip, with strong 

 teeth on the interior margin. 



31. E. Cressonianus n. sp. — 2\iger. cinereo-birtus, valde puuetatus; 

 clvpei margiriibus lateralibus, puncto frontali et orbitarura sinus, niar- 

 ginibus pronoti, lineaque prae tegulis. post-scutello, rnargineque petioli 

 et 2' segmenti. flavis ; petiolo medio flavescente, puncto apicali iinpiesso, 

 baud in margineni producto ; segruentis 2P-50 fusco-marginatis. £. 

 Total lengtb, 11 mrn. ; wing, 8 mm. 



9. Quite the same form as in Norlonianus, but the mandibles 

 elongate, not truncate, arcuate at tip ; the internal border armed 

 with four strong lobular teeth ; the elypeus emarginate in a 

 little arc of a circle. The thorax not so rugose; not roughly 

 shagreened. but more polished and cribrose with coarse punctures; 

 the metathorax not so coarsely punctured ; the post-scutel with- 

 out any crest. The extremity of the petiole a little margined; 

 its impressed point not intrenching upon the margin. The second 

 segment a little depressed, a little more strongly and less densely 

 punctured. 



Black, with the same ornaments as in Xo?*trmiamis, but of yel- 

 low color ; the antenna? beneath and tip of mandibles ferruginous. 

 Feet ferruginous, blackish at base : the tibia? yellow outside. 

 Wings smoky. The scutel not spotted. 



