The larval Malpighian tubules of Sarcophaga ruficornis Fab. consist of two types of cells, namely principal and stellate cells. The principal cells are characterized by a large euchromatic nucleus, well-developed basal plasma membrane infoldings associated with mitochondria and prominent luminal microvilli containing mitochondria with well-developed cristae. The central cytoplasm of the cells contains clear vacuoles, lysosomes, mineral concretions or spherocrystals, lipid droplets and peroxisomes. The stellate cells are thin with extremely short basal plasma membrane infoldings and luminal microvilli devoid of mitochondria. The ultrastructural features of the principal cells show the characteristic of transporting cells engaged in water and ion transport. The cells are separated by septate junctions. The tubules are richly supplied by the tracheae.
