Insects wear a little suit of armor called an exoskeleton.
Wearing a skeleton on the outside instead of the inside means they can’t grow little by little. So they grow in spurts when they shed their skin. When the old skin gets too small, a soft new one forms below it. The old skin splits down the back, and the insect crawls out. Pretty soon, the new skin expands and turns hard. This usually happens four or five times before an insect becomes an adult and stops growing. These changes from the egg to the adult stage are called metamorphosis.
