The Breakdown of the Thoracic Gland in the Adult Insect, Rhodnius Prolixus

Abstract

The thoracic gland in Rhodnius breaks down and disappears within 48 hr. after the moult to the adult stage. Two factors are involved: (i) The gland suffers some change as the result of going through a moulting stage in the absence of the juvenile hormone. (ii) It must then be exposed to some humoral action at the time of the adult moult. The source and nature of the stimulus which operates at the time of the final ecdysis are not known. But when the gland has been exposed to these two changes it will rapidly break down even in an environment containing the juvenile hormone.