In complete metamorphosis, the pupa is the stage between the larva and the adult. The full holometabolous sequence is egg, larva, pupa, and imago, the latter being the sexually mature adult.
During pupation, the insect undergoes a major reorganization rather than simply growing larger. Larval tissues are broken down or remodeled, while adult structures such as wings, legs, and reproductive organs develop. Hormones including juvenile hormone and ecdysone help coordinate these changes.
A butterfly’s pupa is commonly called a chrysalis, while a moth may form a cocoon around its pupa. These terms are not interchangeable: a cocoon is a protective covering, whereas the pupa is the insect stage inside or sometimes exposed. Incomplete-metamorphosis insects, such as grasshoppers, do not have a pupal stage; their nymphs gradually resemble adults.