A pupa is the life stage of some insects undergoing transformation.
The pupal stage occurs only in holometabolic insects, those that undergo a complete metamorphosis, going through four life stages; embryo, larva, pupa and imago.
In the life cycle of an insect the pupal stage follows the larval stage and precedes adulthood (imago).
It is during the time of pupation, that the adult structures of the insect are formed whilst the larval structures are broken down.
Pupae are inactive, and usually sessile.
They have a hard protective coating and often use camouflage to evade potential predators.
A chrysalis or nympha is the pupal stage of butterflies.