A number of important caterpillar pests hide themselves in various ways while feeding and are never seen exposed on the foliage. Bagworms hide themselves in silken bags covered with bits of their food plant. The caterpillar inside exposes only his head and front legs as it moves and feeds carrying its bag-like house with it. Most often a pest of conifers, this insect will also feed on sycamore, maple, honeylocust, Asiatic elm, and other broad leaved trees. Controls should be applied when caterpillars and bags are small, like the three on the twig in this picture.
Females are legless and wingless.
They mate and lay eggs without ever leaving their silken homes. 24.1 Males develop into small, brown, free flying moths. Caterpillars which live and feed within large silken webs are called webworms. The large flimsy nests of the fall webworm are a familiar sight along road sides in later summer. The nests grow larger and larger until entire branches are covered.