The pupa is the stage in a butterfly’s (or moth’s) life when it is encased in a chrysalis and undergoing metamorphosis. It does not eat during this stage.
The pupa stage lasts from a few days to many months (some butterflies overwinter in the pupa stage, and the adult emerges in the spring).
The pupa of a butterfly is called a chrysalis (derived from the Greek word for gold). The chrysalis of many butterflies (like the Nymphalidae and Satyridae families) are suspended from a silk pad and abdominal hooks. Others (like like swallowtails and sulphurs) also have a silk girdle supporting their mid-section. About a day before the adult butterfly emerges, the chrysalis of many species (including the monarch) becomes transparent.