The changes that occur in a developing insect can be dramatic and involve major changes in body form. Insects such as bees and butterflies undergo a developmental process called complete metamorphosis. Starting out as a caterpillar (a larva), a butterfly feeds voraciously and goes through a series of growth stages called instars, which are separated by molts. The last instar builds a cocoon and enters into a quiescent, transformative state called a pupa. The tissues of the pupa are extensively remodeled to form the adult body, which is entirely different from that of the larva. The larval butterfly crawls and eats vegetation; the adult butterfly flies and eats flower nectar. Many other species of insects undergo incomplete metamorphosis, which involves less extreme changes of body form. These insects also go through a series of instars, getting bigger with each molt, but the last juvenile instar simply molts into the adult form with all of the essential adult body parts. Molting involves shedding the skin, or in many cases the rigid exoskeletons, and therefore requires coordination of cellular processes in the entire epidermis of the animal. Both complete and incomplete *metamorphosis require integrated processes in all parts of the insect body.