Cocoon Pupa

the tough brown cocoon of emperor gum moth

a cocoon casing spun of silk many moths , caterpillars, , numerous other holometabolous insect larvae protective covering pupa.

cocoons may tough or soft, opaque or translucent, solid or meshlike, of various colors, or composed of multiple layers, depending on type of insect larva producing it. many moth caterpillars shed larval hairs (setae) , incorporate them cocoon; if these urticating hairs cocoon irritating touch. larvae attach small twigs, fecal pellets or pieces of vegetation outside of cocoon in attempt disguise predators. others spin cocoon in concealed location—on underside of leaf, in crevice, down near base of tree trunk, suspended twig or concealed in leaf litter.

the silk in cocoon of silk moth can unraveled harvest silk fibre makes moth economically important of lepidopterans. silk moth domesticated lepidopteran , not exist in wild.

insects pupate in cocoon must escape it, , either pupa cutting way out, or secreting enzymes, called cocoonase, soften cocoon. cocoons constructed built-in lines of weakness along tear inside, or exit holes allow one-way passage out; such features facilitate escape of adult insect after emerges pupal skin.