Functions of the Corpus Allatum of Insects

Abstract

IT was suggested recently¹ that the active substance (moulting hormone) which initiates cell division in the epidermis of Rhodnius and so induces moulting, and the substance (inhibitory hormone) which restrains metamorphosis until this insect is full-grown, are both secreted by the corpus allatum. By transplanting the corpus allatum from a younger insect (4th instar) into an older one (5th instar), which then develops into a nymph instead of an adult, it has since been proved that the absence of metamorphosis in the young stages is certainly dependent on the secretion of this gland; though it is still uncertain whether there are really two hormones or only a single one in different concentrations. Further, both moulting and inhibitory effects are non-specific: both can be produced in Rhodnius by appropriate secretions from bugs of the allied genus Triatoma.