Abstract
Three types of haemocytes of a wild silkworm, Philosamia cynthia ricini, which appeared on the fat-body cells during metamorphosis, were studied by an electron microscope. The first type of haemocytes included three kinds of lipid-like droplets coinciding with the fat droplets in the fat-body cells and vacuolar bodies with digested materials. They may be classified as granular cells as compared with the haemocyte classification of Bombyx by NITTONO (1960). The second one included bodies with lysosome-like characteristics, with undeveloped intracellular organelles in the cytoplasm. They may also be classified as the other type of granular cells. The third was a spindle-shaped one with several pseudopods. In the cytoplasm, developed intracellular organelles such as granular endoplasmic reticulum and Golgi apparatus were observed. This type also included some lipid-like bodies in the cytoplasm and was classified as plasmatocyte. These haemocytes seem to make contact with the fat-body cells, to perform phagocytic action on the cytoplasmic materials of the latter and to repair both cell membranes and connective tissue sheath after the partial break down of the fat-body cells during metamorphosis.
