Pupa

A pupa (Latin pupa for doll, pl: pupae or pupas) is the life stage of some insects undergoing transformation. The pupal stage is found only in holometabolous insects, those that undergo a complete metamorphosis, going through four life stages; embryo, larva, pupa and imago.

The pupae of different groups of insects have different names such as chrysalis in the Lepidoptera order and tumbler in the mosquito family. Pupae may further be enclosed in other structures such as cocoons, nests or shells.

Some pupae remain inside the exoskeleton of the final larval instar and receive the name of puparium (plural, puparia); the flies of the families Stratiomyidae, Syrphidae and others have puparia.
-Wikipedia