Gypsy moth eggs hatch in early spring. The resulting caterpillar is brownish black with a double row of blue-black and red dots along the back. The body is covered with groups or tufts of hair. Seldom are caterpillars over 3 inches long. Strong winds can pick up these threads and transport caterpillars over many miles.
Caterpillars feed approximately two months and then pupate.
Two weeks later, brown males moths and white female moths emerge. Females seldom fly and are dependent on males locating them. Egg masses usually contain 1,000 eggs and are covered with buff colored hairs from the female's stomach. Moths live less than two weeks. There is only one generation per year.