A pupa, doll, pupae is the life stage of some insects undergoing transformation between immature and mature stages. The pupal stage is found only in holometabolous insects, those that undergo a complete metamorphosis, with four life stages: egg, larva, pupa and imago. The processes of entering and completing the pupal stage are controlled by the insect’s hormones, especially juvenile hormone, prothoracicotropic hormone, and ecdysone. The pupae of different groups of insects have different names such as chrysalis for the pupae of butterflies and tumbler for those of the mosquito family. Pupae may further be enclosed in other structures such as cocoons, nests or shells.