Gen. Char.: Head transverse, linear, fully as wide as the thorax, flat, with a slightly convex tendency; ocelli in a triangle; antennæ short, scarcely geniculated; face beneath the insertion of the antennæ, protuberant; clypeus transverse, margined, convex; labrum transversely ovate, deeply emarginate, in the centre in front; mandibles bidentate, obtuse, the external tooth projecting much further than the second; tongue short, lanceolate, fringed with setæ; paraglossæ not so long as the tongue, abruptly terminated, and setose at the extremity; labial palpi not so long as the paraglossæ; the joints comparatively elongate and slender, and decreasing towards the apex in length and substance; labium rather longer than the tongue, its inosculation straightly transverse; maxillæ about the length of the tongue, broad and lanceolate; maxillary palpi six-jointed, the first joint shorter and less robust than the second, which is also shorter and less robust than the third, which is the longest and most robust of all, the terminal joints more slender, and declining gradually in length. Thorax ovate; prothorax linear, produced into a sharp tooth on each side; mesothorax with longitudinal lateral impressed lines; bosses acutely protuberant; scutellum quadrate; postscutellum inconspicuous; metathorax slightly gibbous; wings with three submarginal cells, and a fourth slightly commenced, the second narrow, forming a truncated triangle, and receiving the first recurrent nervure in its centre, the second recurrent nervure springing from just beyond the centre of the third submarginal cell; legs slightly but rigidly spinose and setose; claws bifid. Abdomen ovate.
The MALES differ, in having the antennæ longer and sometimes moniliform, the lower part of the face and clypeus usually covered with a dense short silvery decumbent pubescence, and they have the metathorax truncated at its base; in other respects they greatly resemble their females.
The insects of this genus may be called glabrous, their pubescence being so slight and scattered, they usually shine brightly, and are more or less deeply punctured; and the abdomen is always partially or entirely of a bright ferruginous red, sometimes verging into fuscous or pitchy.
NATIVE SPECIES.
1. gibbus, Linnæus, ♂♀. 3-4½ lines. ([Plate I.] fig. 3 ♂♀).
sphecoides, Kirby, ♀.
monilicornis, Kirby, ♂.
picea, Kirby, ♂.
2. Geoffroyella, Kirby, ♂♀. 1-3 lines.
divisa, Kirby, ♂.