InS. Holoschista, the eyestalk is provided with four types of neurosecretory cells (NSC) while the thoracic ganglia and the brain each have three types. The activities of certain NSC types of the eyestalk (C and D), the thoracic ganglia (B) and the brain (C) show fluctuations in their secretory activity during the synchronous growth of the ovary and cement glands suggesting their involvement in the control of these organs. Eyestalk ablation experiments on the reproductively quiescent female revealed the inhibitory nature of an eyestalk hormone on the ovarian and cement glands growth. On the other hand, aqueous extract of thoracic ganglia from the mature reproductive females promoted ovarian and cement glands activities, when injected into the quiescent females. But brain extract injection failed to affect the activity of the ovary or cement glands.