Select the images help you identify forest tent caterpillar.
Adult moths lay small brown egg masses that wrap around twigs.
Larvae hatch from egg masses in early to mid-May, about the time aspen leaves are beginning to open. The larva has blue stripes along the sides of its dark, hairy body. Its most identifiable characteristic is the white key-hole or footprint-shaped spots along the back of its body. Mature caterpillars grow to 2 to 2½ inches.
Mature caterpillars spin whitish silk cocoons attached to vegetation, buildings, and other stationary objects from early to late June.
Adult moths are small and tan. They can be attracted to lights in large numbers in mid-July.
Learn about the forest tent caterpillar life cycle on the University of Minnesota Extension forest tent caterpillar website.