The following species are very interesting, as they posses no spurs at the end of the tibiæ. From N. America are for species, two not yet described. All agree in the following characters: They are very slender, more or less hairy or villous, head small, narrow; antennæ long, as long as head and thorax, or at least prothorax, stout, cylindrical, becoming gradually thicker but not clavate; labial palpi a little longer than the maxillary ones; last joint very little thickened to the middle, where a superior depression makes the apical half about cylindrical, legs short, not very thick, with numerous spines and bristle, but no spurs; first joint of tarsi longer than the following, but shorter than the apical one; abdomen of male considerably longer, of femal shorter than the wings; appendages of male short approximatel cylindrical with storng hairs and spines, enlarged at the base to reach the dorsum of abdomen; between them below a very small triangular plate; female with two short flat appendages inferiorly; upper part rounded, split in the middle; wings elongate, narrow, enlarged to the bluntly pointed tip; post-costa oblique; venation dense, and sprinkled more or less with brown; costal space of front wings with two series of areoles (one species) or with one series, but the transversals in the apical half (or less) forked; at the extreme base of the hind wings of the male is a small white free knob, homologous to the larger and darker knob of Palpares and Acanthaclisis. The larva of one species is known; it differs from all others and was described by me as perhaps belonging to Acanthaclisis congener.