1. The involvement of corpora allata and juvenile hormone in vitellogenin synthesis in the Cecropia silkworm was examined. 2. Allatectomy of diapausing pupae did not alter the pattern of 3H-leucine incorporation into vitellogenin during their late pharate adult development. 3. Allatectomy of early fourth and fifth instar caterpillars did not prevent the appearance of vitellogenin in these operated animals when they had transformed into miniature pupae or pupal-adult intermediates. 4. Injection of a synthetic dl-JH into isolated diapausing abdomens did not stimulate the incorporation of 3H-leucine into vitellogenin. 5. It is concluded that corpora allata and juvenile hormone are not required for the initial appearance and synthesis of vitellogenin in the Cecropia silkworm.