What is the pupa of a butterfly commonly called?

The pupa of a butterfly is commonly called a chrysalis.

A chrysalis is the immobile pupal stage between a caterpillar and an adult butterfly. Inside it, the larval body is reorganized as adult structures such as wings, compound eyes, and reproductive organs develop.

“Chrysalis” specifically refers to a butterfly pupa, while “cocoon” is a silk or other protective covering spun by many moth caterpillars before pupation. A chrysalis itself is not generally a silk case. Some butterfly pupae are attached to plants by silk, but the pupa remains exposed.

The word comes from the Greek chrysos, meaning “gold,” because some butterfly pupae have metallic golden markings. The pupal stage can last days, weeks, or longer depending on species, temperature, season, and dormancy.