The matured oocyte in the ovariole of Pieris rapae L. and the embryo before the hatching from the breeding were observed. 1. The oocyte cortex before breeding has many finger-like projections but after the breeding the projection was disappeared and numberless microvilli existed between the tell forming ovariole sheath and chorion. 2. The formation of yolk protein took place in the site of Golgi complex and E.R. 3. Glycogen particle existed in the oocyte of Pieris rapae L. 4. On the beginning of the development, microorgans were in the existence of islet form. 5. Blastodermal cells were on the remarkably undifferentiated condition