Luna Moths are huge moths, with a wingspan of four and a half inches. They have a white body, pinkish legs, and huge pale green wings. The hindwings have eyespots and long tails. They fly, only at night, in Spring and early Summer. The female Luna Moth lays eggs on the bottom of Black Walnut leaves.She lays about 200 eggs in small groups. You can tell a male from a female, because males have larger, bushier antennae. William Welch ©a natural selection Once the eggs are laid, it takes about 10 days for them to hatch.he caterpillars will continue to eat and grow, molting their skins as they grow. They will do this five times over a period of three to four weeks. When the caterpillar is fully grown, it will be 2 1/2 inches long and ready to become a pupa. It will spin silk from near its mouth and wrap itself in a leaf.