The leg of the last instar larva, and especially the pharate pupa, of Tenebrio molitor (Coleoptera) shows considerable restoration ability. Restoration refers to the regeneration of leg structures removed during the last larval instar. This process involves only those tissues adjacent to the cut surface. At each level of the leg, amputation before a characteristic time leads to the restoration of a complete leg, but thereafter the new segments formed are hypomorphic or just lobes. After an amputation close to the pupal ecdysis, fragments are obtained, and these incomplete structures show that the restoration process has ceased. Just before the pupal ecdysis the leg is withdrawn from the cuticle, so a very late amputation does not effect the leg tissue and a complete pupal and adult leg is formed. The whole of the larval leg participates in adult leg morphogenesis, and histological techniques demonstrate a great correspondence between larval and adult leg segments. The larval trochanter, however, forms the adult trochanter and the proximal part of the femur. The larval tibia forms the adult tibia plus tarsus, except for the adult claws which develop from the larval tarsal claw.