Hodges (1998) defined this family by the autapomorphy of the gnathos consisting of a sclerotized band fused to the tegumen and that is mesially expanded and ventrally directed. In addition this family shares the following: 1) frenum present, 2) forewing with CuP usually absent, 3) hindwing with outer margin excavated posterad of the apex, 4) larvae with secondary setae, and 5) larva with 2L setae on the prothorax. In addition, Ocelli are absent, the antennae are often thickened and long in males, and the maxillary palpi are 4-segmented and folded over the base of the proboscis (Scoble, 1992). Larvae have dense, branched secondary setae on verrucae and crochets arranged in a uniordinal mesal penellipse or in a pair of transverse rows (Scoble, 1992).
The family has been divided into three subfamilies. Torodorinae is defined by a thorn shaped uncus that tapers to an acute apex, Lecithocerinae has an uncus with a narrow base and broad, bilobed apex and a narrow sclerite extending from the base of the tegumen to the mesial surface of the valva, and Ceuthomadarinae is defined by the absence of a haustellum, apophyses anteriores that usually are as long as the bursa copulatrix, and the narrow sclerite that extends from the base of the tegumen to the valva.
Larvae feed on dead plant tissue and detritus.
The family includes more than 500 species in 90 genera and are primarily Indoaustralian, although some species occur in the southern Palearctic and Africa.
References: Clarke (1955a, 1965), Common (1990), Gozmany (1978), Janse (1949-54, 1958-63), Kanazawa (1986), Moriuti (1982), Piskunov (1981), Sattler (1973).