SCLEROTIZATION IN THE BLOWFLY IMAGO.

N-acetyldopamine has been identified as a dihydroxyphenylalanine metabolite in the blowfly imago during eclosion. The activity of the dihydroxyphenylalanine decarboxylase, the main enzyme responsible for its formation, which is minimal during the pupal stage, increases I day before eclosion. The similarity of dihydroxyphenylalanine metabolism in Calliphora during eclosion and during puparium formation justifies the assumption that N-acetyldopamine can be regarded as the sclerotizing agent of the imaginal cuticle. It is concluded that the formation of this substance is under the control of ecdysone.