67 species. Wingspan 8-15mm. A large family of narrow elongate moths which rest with porrect antennae. The imagines of many species are very similar in appearance and often need dissection for accurate identification. Their larvae mine in leaves or seed heads , then construct portable cases from silk and plant material using them as habitations from which they mine characteristic blotches from leaves or bore into the seed heads. These leaf mines are round translucent blotches which do not contain any frass and they have a small round hole in the under surface of the leaf where the larva attached its case before mining into the leaf. Some species have initially small curved cases in the autumn in which they overwinter attached to a twig or stem of their foodplant. They then mine into a leaf and cut pieces out of mined leaf and construct larger cases, which they may enlarge as they grow, or change to a bigger one, before pupating in the case, often attached to a stem or on the upper surface of a leaf of the foodplant. A few species make a black case from a mixture of silk and frass and feed in the spring by eating holes in leaves. The seed head feeding species either make silken cases or sometimes make cases entirely or in part from a seed head of the foodplant. Many species are most easily identified from the often characteristic form of their cases and from the foodplant.