part_of process of oogenesis formation of ovarian follicles During mosquito embryogenesis pole cells form after cleavage energids have entered the posterior periplasm with its polar granules. The pole mirgrate in to two groups and settled in the 6th abdominal segment, where they become surrounded by mesodermal sheaths and form the gonad rudiments. The pole cells are now called primordial germ cells. By the 4th larval instar the ovaries are already distinct and contain cell clusters within a matrix of smaller cells, the interstitial tissue. By the early pupal stage each ovary has reformed into a group of ovarioles. Later in the pupal stage each ovariole differentiate into a germarium amd a vitellarium compromising one, two or even three ovarian follicles. IDOMAL:0002092 IDOMAL:0002092 idomal_namespace physiological process of malaria vector