The luna moth's eggs are brown. The caterpillar is green. It has bright red spots on its body. There are two yellow stripes that run down each side of the body. The caterpillar will grow to 6.5 cm long. The luna moth caterpillar is similar to the polyphemus moth ("Antheraea polyphemus") caterpillar. The polyphemus moth caterpillar does not have the yellow stripes on its body. The luna moth's cocoon is made of dead leaves on the ground. It overwinters (spends the winter) as a cocoon. The luna moth has one brood (a brood is a group of offspring) each year in the northern part of its range. It has three broods each year in the southern part of its range.