STUDIES ON THE OVARIAN DEVELOPMENT IN THE HOUSEFLY, MUSCA DOMESTICA VICINA MACQUART

I. STAGES OF OOGENESIS AND THE FUNCTION OF THE FOLLICLE

Abstract

The ovarian development of the housefly, Musca domestics vicina Macquart was studied histologically and biochemically. During the course of ovarian development, the ovarian weight increased remarkably following the enlargement in size of the follicle; these growth curves showed similar patterns. In the developing ovary, protein and lipid accumulated abundantly, and a small amount of glycogen was observed in the later stages of oogenesis. From the cytological observations, oogenesis could be divided into 7 stages; the follicledifferentiating stage (Stage 1), the follicle-growing stages (Stages 2, 3), the vitellogenic stages (Stages 4 to 6) and the mature egg stage (Stage 7) . The oocyte initiated development at early stages of oogenesis; the nurse cells and follicular epithelial cells were considered to fulfil important functions with regard to the growth of the oocyte.