"...an evolutionary elaboration of the molting phenomenon, is called metamorphosis. Butterflies have what is called complete Metamorphosis: a larva, or a caterpillar, becomes a pupa, and the pupa becomes an adult butterfly. Hatching from the egg is not a molt; the larva simply grows inside the egg and chews its way out. Larvae molt (typically three to five times) to bigger larvae, the mature larva molts to a pupa; the pupa molts just once, to an adult, and the adult, which might live only a week, neither grows not molts."