17 species in 1 genus are known from Block Island. This family of tiny to minute and usually dull-colored moths is represented in the Nearctic region by hundreds of species, the majority of which are undescribed, in a single genus. The larvae construct protective and camouflaging cases taking a variety of forms, and they extend their bodies out from within their cases to either mine leaves through a small hole chewed through the epidermis or else feed on seeds.