_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, ♂. 3. _fuscipennis_, Germar, ♂♀. 4½-6 lines. GENERAL OBSERVATIONS. This genus is named from _σφὴξ_, a wasp, from its apparent resemblance to some of the sand wasps.