Tent caterpillars make their webs at tree crotches and are spring pests. The fall webworm adult is an attractive white tiger moth with black markings. The dark markings of spots and stripes may be few or extensive. Adults emerge from pupae in leaf litter during May, but the first generation goes unnoticed. A second generation, which emerges in late July or August, is more likely to be pestiferous.
Females lay light-yellow eggs in egg masses numbering several hundred eggs.
Eggs hatch quickly in the second generation. Larvae are gregarious and stay together. They feed on host leaf material inside the web, which expands as the larva matures. The large webs are conspicuous, expanding to 2 to 3 feet in length as the caterpillars get larger. Larvae mature in about six weeks.