Mating happens from afternoon to early evening. Egg-laying begins at night. Females are attracted to lights, but males are not. Females lay 2-12 eggs in a cluster on the host plant (the host plant is the plant that the caterpillar eats). The yound caterpillars feed together on the underside of leaves. They are greenish yellow and striped with black. The older caterpillars do not feed together. They are almost all green except for 4 red knobs above the thorax and 1 yellow knob on the eighth abdominal segment. The caterpillar makes a cocoon within a leaf. The cocoon is firmly attached to the lower branches of the host plant. The Promethea Moth has 1 brood in the northern part of its range (which flies from June-July). It has 2 or more broods in the southern part of its range (which fly from March-May and again from July-August).