Haemopoiesis in Lepidoptera. I. The multiplication of circulating haemocytes

Abstract

Haemopoiesis in Lepidoptera is doubtless accomplished to a large extent by mitosis of the circulating haemocytes. but there are some anomalies with regard to certain classes. Granular haemocytes and spherule cells are the only classes that divide frequently enough to account alone for their continued increase in numbers. Prohaemocytes divide frequently, but their numbers do not increase markedly. There is little doubt that they differentiate exclusively to plasmatocytes, which rarely divide themselves but continue to increase in numbers during larval life. An increase in plasmatocyte size and numbers after the fourth instar, when the mitotic index of prohaemocytes is declining, suggests an alternative source as well. Oenocytoids never divide, and undoubtedly derive from a separate source.