Abstract
Mitochondria of the posterior silk gland cells show a series of characteristic morphological changes in the later pupal and in the prepupal stadium. In the fourth instar and in the very beginning of the fifth instar round or oval mitochondria predominate which are distributed rather uniformly in cytoplasm while in the fifth instar, elongated mitochondria predominate which are arranged radially along the canal system. In the prepupal stadium a number of cup-shaped mitochondria appear which engulf a small portion of cytoplasm. It was suggested that the formation of such cup-shaped mito- chondria in the cells is induced by a rapid increase in the ecdysone titer in the prepupal stadium and that these mitochondria probably play some role for the catabolic processes in the same stadium.
