Ligation of the largest preovulatory follicle (F1) or the second largest preovulatory follicle (F2) delayed terminal oviposition for at least 2 h. Ligation of the fourth or fifth largest preovulatory follicle had no effect on the time of terminal oviposition. The conclusion reached was that some factor produced by the most mature follicles in the ovarian hierarchy influenced the timing of oviposition. Since the terminal oviposition occurs independently of ovulation, the authors concluded that the influence of the F1 and F2 follicles was independent of any preovulatory endocrine changes.