[citation needed] Formerly, this genus was included in the cosmet moths (Cosmopterigidae).

In addition, like in some related moths the scape is short and bears a comb.

Most characteristically though, the eighth sternal and fourth to seventh abdominal segments are modified, the former forming epitygmata ("genital flaps").

Like in some related moths, the males also have a tuft of hairs on the hindwing underside, which can be folded into a pocket in the wing cell.

As regards other features of the female genitals, the ovipositor is long while the ostium is usually well sclerotized and protrudes, but may be recessed into a deep pit in the seventh sternal segment.