Tibiæ calcarate; spurs as long as the two basal joints, or a little shorter; antennæ longer than head and thorax, stout, cylindrical, a little thicker to tip, which is bluntly pointed, but not clavate; palpi about equal, last joint of labials (except in B. longipalpis) with the basal two thirds inflated, fusiform; abdomen long, slender, about half longer than the wings (male); or as long as the wings (female); male appendages very short, less than half the lenght of last segment, stout, cylindrical, very hairy and spinous; a very small ventral triangular plate below and between them.