Chrysalis

Chrysalis and pupa: what is the difference

Chrysalis (from Greek χρυσός — gold) is the pupa of a day-flying butterfly (lepidopterans of superfamily Papilionoidea). The term applies specifically to day-flying butterflies; moths usually form cocoons — pupae wrapped in silk.

The name reflects appearance: in many species the chrysalis surface has golden or silvery spots and shiny bands — an optical effect from special chitin structure.

Structure of the chrysalis

A chrysalis is the pupa of a day-flying butterfly, covered by a hard chitinous case. Outlines of the future butterfly's wings, legs, antennae, and eyes are visible — as if “cast” under the chitinous shell.

How the chrysalis is attached is characteristic of each family:

• Swallowtails (Papilionidae) and whites (Pieridae) — hang head up, held by a silk girdle around the body and a cremaster (hooks at the base)
• Nymphalids (Nymphalidae) — hang head down, attached only by the cremaster to a silk pad

What happens inside

The chrysalis looks calm on the outside. Inside histolysis occurs — literally “dissolution”: caterpillar tissues break down into a uniform nutrient mass. This mass contains groups of stem cells — imaginal discs that have stored “blueprints” of adult organs since the larval stage.

From imaginal discs are built anew:

• wings with veins and scales
• compound faceted eyes
• proboscis
• antennae
• flight muscle
• reproductive organs

This process — histogenesis — takes from several days to several months depending on species and conditions.

Duration of the stage

Chrysalis duration varies greatly:

• 7–14 days — most summer species (small tortoiseshell, brimstone, whites)
• 1–3 months — species with one generation per year (Apollo, some fritillaries)
• overwintering in the chrysalis — some species diapause as pupae (large white, small white, black-veined white)

Color and camouflage

Chrysalis coloration is often cryptic — matching bark, dry leaf, or stem. Some species can change chrysalis color depending on background: this is phenotypic plasticity.

Golden and silvery spots (which gave the name “chrysalis”) are most pronounced in nymphalids — peacock, mourning cloak, fritillaries. They may serve as extra camouflage, mimicking water glints or dewdrops.

Eclosion: the butterfly emerges

When development is complete, imago breaks the chrysalis shell from inside — this moment is eclosion. The butterfly pulls itself through a slit at the head end, grips the empty chrysalis with its legs, and begins to expand its wings.

The full glossary is in the glossary section.