Insects grow through the process of metamorphosis, meaning that they undergo change. Insect groups that undergo a complete metamorphosis include beetles, moths, butterflies, sawflies, wasps, ants, bees, and flies. All these groups begin their life cycle as an egg. The egg hatches into a larva such as a caterpillar, grub, or maggot that feeds, molts (sheds its skin), and grows larger. The larva goes through an inactive pupa stage for example, it is wrapped up in a cocoon and emerges as an adult insect, such as a butterfly or beetle, that looks very different from the larva it once was. Other insect groups do not go through a complete metamorphosis, but rather experience gradual changes as they turn into adults. These include scales, aphids, cicadas, leafhoppers, true bugs, grasshoppers, crickets, praying mantises, cockroaches, earwigs, and dragonflies. Immature forms of these insects are called nymphs. The nymphs grow and gradually change size, shedding their skin along the way. After a final molt, the full adult form emerges.