substage of immediately preceded by oogenesis developmental stage oogenesis stage S1 oogenesis stage S2 Oogenesis stage that begins when the cyst leaves the germarium (from this point the cyst is referred to as an egg chamber). During this stage, polyploidation of the nurse cells begins, they reach a ploidy of 8C, and follicle cells start to divide. Temporal ordering number - 10020. FlyBase_development_CV FBdv:00005262