The characters of this genus are given at length under the name of Tenthredoides (Proc. Ent. Soc. Phil., iv., p, 29o), which airpears to be synonymous. It may be easily recognized by the short robust body, rather lalge transverse head, stout legs, broad ampie wings (which are, gencrally fuliginous). and especially by the form of the marginal cell, which is rather suddenly constricted (or somewhat reclivate) at tip of second sub-marginal cell, and thence narrowed to the apex, which is somewhat incurved, and reaches the extreme apex of the wing; this, as well as the second and third submarginal cells, are indistinctly defined, the nervures being sub-obsolete.