G8 HYMENOPTERA OF AMERICA. [PART I. 



Division OMICRON. 

 (Sadss. Vespides, I, 71 ; III, 133, 148.) 



Body sericcus. Clypeus ? bidentate, often bicarinate. Thorax 

 very short, cubical before, globular behind. Petiole very elongate 

 — pear-shaped, not campanulate in the middle, swollen into a 

 polished boss at the extremity; its margin bordered by a polished 

 cordon, preceded by a transverse channel or constriction, but 

 without impressed point at the extremity ; the marginal cordon 

 forming a simple yellow (or black) line, without indentations as 

 in Division a. The rest of the abdomen more or less depressed, 

 never compressed, often polished. Second abd. segment having 

 its colored border followed by a second lamellar margin; second 

 cubital cell short. Antennae of males with a very small terminal 

 hook, or even quite destitute of hook, as in the females. 



Ornaments. — The colored border of the posterior margin of 

 prothorax more pronounced than the anterior one ; fascia? gene- 

 rally not wide. The petiole often ferruginous in the middle and 

 on the sides, its hind margin with a yellow band, and often also 

 ornamented on each side by an oblique yellow line fused with the 

 yellow border. 



This section only contains species of small size. The head 

 and the thorax are very large compared with the abdomen ; they 

 are sometimes cribrose with great punctures and covered with a 

 silvery pile, in place of being hairy, sub-woolly as most species of 

 the Division Alpha. The clypeus is more or less bidentate, never 

 distinctly truncate, and the ocelli have a tendency to arrangement 

 in a straight or arcuate transverse line. The emargination of 

 the eyes is situated very low, almost in the middle of their height, 

 and these organs entirely cover the sides of the head, which is 

 short. The antennae are inserted very low, sometimes below the 

 middle of the head. 



The thorax is drawn together so as to become at times wider 

 than long. In front it holds in effect to the cube, being squarely 

 cut; behind it is rounded, tending rather to the globular form. 

 The part situated before the scutellum is always sensibly wider 

 than long, and the prothorax is not in the least attenuated ; on the 

 contrary, it is angulate, squarely cut, and forms the wider part of 

 the thorax. The scutels are quite driven back upon the slope of 

 the metathorax, which is completely drawn together, having its 



