The Swedish entomologist, C. G. Thomson, first separated this family as a tribe in 1871. It had been placed previously with the Lydides, with which it had no affinity whatever. In the structure of the head, thorax and abdomen the species approach closest to the Hylotomidae, Perreyiidae and the Pterygophoridae. The multiarticulate antennae, however, separate them at once from the former; the distinct anal cell in the hind wings separates them from the Perreyiidae, which have none; while from the last, to which they are undoubtedly most closely allied, they are readily distinguished by having a distinct lanceolate cell in the front wings.