The larval haemolymph of three cyclorrhaphous dipteran flies, Sarcophaga ruficornis Fab., Musca domestica L. and Chrysomya megacephala Fab., possesses five different types of haemocytes: prohaemocytes; plasmatocytes; granulocytes; spherulocytes; oenocytoids. In addition, vermicytes are found in the haemolymph of S.ruficornis and adipohaemocytes in the haemolymph of M. domestica. The total haemocyte counts in the three dipteran flies show an increasing trend throughout the larval stage, attaining a peak value in the freshly formed white puparium stage and declining thereafter. The differential haemocyte count shows a decline in the number of prohaemocytes with an increase in the number of plasmatocytes, granulocytes and spherulocytes.

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.