Acentria ephemerella adults are 5–9 mm long and range in color from white to tan, with darker bands on the body. Males and some females have creamy-white, feathered wings, though most females are wingless. Females lay 100–300 eggs on host plants in early summer. Larvae grow up to 12 mm long and are greenish-transparent. Larvae mine plant leaflets until large enough to build shelters out of plant material. Fourth- and fifth-instar larvae feed on stem tips before pupating within cocoons attached to plant stems. There are up to two generations per year; new adults emerge in late summer, and larvae overwinter on lower plant stems.