The function of the Corpus Allatum in the Growth and Reproduction of Rhodnius prolixus (Hemiptera)

ABSTRACT During its growth Rhodnius prolixus moults five times. At the first four ecdyses its characters change comparatively little; but at the final ecdysis, when the insect becomes adult, it undergoes a definite ‘metamorphosis’. In an earlier paper (Wigglesworth, 1934) it was shown that the initiation of each moult and the prevention of metamorphosis until the final moult are both effected by hormones circulating in the blood. It was suggested that two factors are involved: a ‘moulting hormone ‘which initiates cell division in the epidermis, and an ‘inhibitory hormone ‘which prevents the development of adult characters until the insect is full grown. For purposes of description this hypothesis of two active substances will be retained; although, as previously pointed out, it may ultimately be proved that a single substance in different concentrations is responsible for both effects.