The egg masses are visible in winter, are grayish-brown and about one inch long. As soon as the eggs hatch in April or May, the caterpillars begin eating leaves and create “tents” – white, silky shelters that cover the forks and tips of tree branches and shrubs. They feed during daylight and return to their tents at night.

The caterpillars are easy to recognize. They have a yellow checkered pattern with a blue dotted line down their backs, and can be three inches long when mature. The caterpillars molt four times over a period of five or six weeks, then stop eating. They choose a place to spin a cocoon and lay their eggs, and moths emerge about two weeks later. The adult moths mate immediately, lay eggs, and die a few days later; the eggs winter over until spring, when the whole process begins again.