An imaginal disc is one of the parts of a holometabolous insect larva that will become a portion of the outside of the adult insect during the pupal transformation. Contained within the body of the larva, there are pairs of discs that will form, for instance, the wings or legs or antennas or other structures in the adult. During the pupal stage, many larval structures are broken down, and adult structures, including the discs, undergo rapid development.