Silk moth caterpillars make cocoons as a safe place to change into adults. After feeding all summer, the larva weaves around itself and spins a flask-shaped, silken cocoon that hangs from the host shrub or young branch. In the summer, the larva transforms into a pupa (pupates), ending up in a cocoon approximately 2-3 inches in length and 1 inch in width. Throughout the fall and winter months, the pupa gradually undergoes metamorphosis while in the cocoon stage and by late winter or early spring, the adult moth emerges (aka “eclosing”) from its pupal case in May or June. The adult silk moth survives for only 1-2 weeks – it’s sole function is to mate soon after eclosing, lay eggs, and perish.