Abstract
1. When active prothoracic glands or brains are implanted into diapausing Chilo larvae, extramoulting followed by prothetely occurs immediately after operation. But, in case of brain implantation, development towards pupation in some larvae, which have not initiated prothetelic moulting, is somewhat accelerated as compared with that of non-operated controls.
2. Active prothoracic gland from Barathra prepupa is able to cause the immediate termination of diapause in decapitated Chilo larva as well as its isolated abdomen.
3. Brain obtained from Chilo larva at critical period can also induce abrupt termination of decapitated, diapausing Chilo larva.
4. If diapausing Chilo larva is decapitated so as to remove corpora cardiaca and allata but leaving the brain intact, the termination of diapause occasionally occurs.
5. It is suggested that there is a hormone centre in the head of diapausing Chilo larva, which is inhibitory in action on the development of larva. This centre is considered to be corpus allatum itself.
6. There is a possibility that the inactive brain can be abruptly changed to active one in the medium where the inhibitory principle likely from corpora allata is lacking.
