Abstract
The prothoracic glands taken from 6-day-old larvae in the final instar of the cabbage armyworm (Mamestra brassicae L) were well maintained for considerably long term in vitro.It was ascertained that these prothoracic glands relased hormonal agent which induces the moulting of the integument of the diapausing rice stem borer (Chilo suppressalis WALKER)larvae in media such as CSM-2F, Grace's medium and Ringer-Tyrode's solution. The prothoracic glands from the diapausing pupae of the cabbage armyworm, however, did not show any activity to initiate the moulting of Chilo-integuments. The homogenates of active prothoracic glands did not indicate the moulting function in vito. The hormonal agent released from the active prothoracic glands was acetone soluble and heat stable (90°C, 10min). The implication of these results were discussed.
