A division (also known as Holometabola) of the subclass Pterygota, including those insects that undergo complete metamorphosis during their life cycle. That is, individual development goes through four distinct stages: egg, larva (trophic), pupa (reconstructive), and adult (reproductive). The larval and adult stages often live in very different adaptive zones and have very different life forms, necessitating a quiescent pupal stage in which extensive restructuring takes place. Typically growing through a sequence of immature forms (instars) punctuated by integumental molts, the larval instars correspond to those of nymphal Exopterygota in most ways, but are distinct in having wings, internalized as tiny wing buds. The buds are tucked out of the way of the larva, grow very rapidly in the pupal stage, and expand and quickly become functional in the newly hatched adult.