Largely because of the secretive and sometimes omnivorous feeding habits of the larva, surprisingly little is known about the biology of most species in this relatively well known family of moths. Eggs  are inserted into plant tissue in which the larva may or may not feed (Heath and Pelham-Clinton 1976, Nielsen 1985). According to Chretien  (1894), during late spring and early summer the eggs of Nematopogon metaxella are inserted into any convenient herbaceous plant. Upon hatching, the larva immediately drops to the ground where it constructs a flattened, oval case from soil particles and eventually dead leaves (Chretien 1894). The larva feeds on both living and  dead plants and does not complete its development until the following spring. Kuroko (1961)reports a somewhat different life history for  Nemophora raddei that may more accurately reflect the univoltine norm for the family. In this species the eggs are inserted into the ovaries of Salix sieboldiana in spring. The first instar larva  feeds on the ovules as well as the ovary wall. After moulting, it constructs a small, oval case and descends on a silken thread to the ground where it prefers to feed on dead leaves of the host Salix and Castanea crenata. The mature larva (6th instar) pupates near the end of October, with the adult emerging the following spring. The eggs of most Adela are inserted into the flower ovary of their host wherein the first instar larvae feed on the developing seeds. From the second instar on, the larvae become casebearers and feed on the lower or fallen leaves of their host (Heath and Pelham-Clinton 1976). First  instar larvae of some Adelidae may mine leaves (Common 1990). Over 20 families of angiosperms and one gymnosperm (Pinaceae) have  been reported as hosts (Küppers 1980).