developmental gates previtellogenic gate IDOMAL:0002280 IDOMAL:0002280 The primary follicles may develop directly to Christopher's stage IIa or IIb after emergence, or may develop to this stage only after the females have fed. The primary follicles of anautogenous females then enter the previtellogenic resting stage, remaining in it until the female has taken a blood meal. The primary follicles of autogenous females pass the previtellogenic gate without arrest, demonstrating the conditional nature of the gates. idomal_namespace