Synthesis of blood and cuticular proteins in late pharate adults of the cecropia silkmoth

Incorporation of tritiated leucine into blood and cuticular proteins of male Hyalophora cecropia was monitored during the final third of pharate adult development. We found no changes in specific activity of the total blood proteins, but there were conspicuous alterations in the banding pattern obtained by acrylamide gel electrophoresis. The specific activity of the cuticular protein extract decreased with age, but the cause of this decline is not obvious. These final stages of exocuticle formation do not involve the appearance or synthesis of new blood or cuticular proteins.