Metamorphosis of imaginal discs of Drosophila melanogaster.

Imaginal discs ofDrosophila melanogaster larvae, 24-53 hrs after oviposition, were transplanted into mature immobile larval hosts. The transplants did not respond to the hormonal stimuli of metamorphosis, but instead completed their larval development. When reinjected into mature larval hosts, they now differentiated the full set of their presumptive imaginal structures. The process of acquiring competence for metamorphosis appears to be independent of the hormonal conditions.