(A) 0, 9, and 14 h after the injection of "human chorionic gonadotropin" (hCG) in gravid females just before entering a breeding pond. Ovulation has not yet occurred.

(B) 18 h after the injection. Female in the process of ovulation. More than half of ripe ova are ovulated within the coelom. Part of them enters the pars recta of the oviducts.

(C) 32 h after the injection. All ripe ova (i.e., a full clutch) of approximately 100 have been ovulated. Most of them enter the pars convoluta of the oviducts, and the succeeding ovisacs (i.e., uteri).

(D) 50 h after the injection. Egg sac formation is completed in the distal parts of the ovisacs (i.e., dilatable ovisacs). This is the condition of females prior to oviposition.

Also see histological changes in ventral glands from 18 h into 32 h after the injection, and changes in body shape in females, which correspond to ones between 0 h and 50 h.