Post-larval insects are a stage of insect development that occurs after the larval stage and before the adult stage. Pupas are the intermediate stage between larvae and adults in the life cycle of many insects, such as butterflies and moths. During this stage, the insect undergoes metamorphosis, which is the process of transformation from an immature form to an adult form. During pupation, the insect's body undergoes dramatic changes, including the formation of wings and other adult features.