The larva of the Polyphemus moth , pictured in the Saturday Saturniids post a few weeks ago, spins a silken cocoon in the leaves of its host tree. The keen observer may sometimes spot these silken sanctuaries suspended from the twig of a birch or willow oak as the leaves begin to thin out in the fall.
Occasionally, Saturniid cocoons share their branches with a slender, elongate sack of silk which tapers near the top and bottom.
These little pouches are cleverly disguised with ornaments of organic matter, and can sometimes be quite numerous, particularly in their preferred evergreen host trees.
This is the home of the evergreen bagworm. The male lugs its "mobile" home around with it until time to pupate. Then it will secure its bag to a limb with silk and seal off the opening. It will emerge in a month or so as a bee-like moth and seek a mate. In this case the bag lady is a real homebody. She never leaves her cocoon; mating through an opening in the cocoon and then remaining in the cocoon with her eggs through the winter.
The young will hatch in late spring from her carcass and set out upon a silken strand to begin building their own cocoon. Such is the life of a bagworm...