Labdia sp. mines phyllodes of several species of Acacia possessing large phyllodes. Its development in, and association with, A. saligna are outlined; the four larval instars all feed mainly on epidermis and palisade tissue, and pupation occurs within the mine. Faeces are extruded from the mine but retained in a mass on the outside and may protect the pupa. The life history and feeding biology of Labdia are compared with those of Acrocercops plebeia (Turner).