Metamorphosis
It pays to know what insects look like throughout their life cycle, because they metamorphose, or change form, as they grow. Born with rigid or semi-rigid outer skins, insects would have a difficult time growing if they weren't able to shed this covering as they outgrew it. Some insects--such as beetles, lacewings, and moths--start life as grublike larvae and then evolve to an intermediate stage at which they are called pupae. Finally after more molting, they assume their adult form, which looks completely different from the earlier stages. Such a total transformation is called a complete metamorphosis.

Most people are familiar with the caterpillar-to-butterfly cycle, but many people are not aware what lady beetles and lacewings look like in infancy. During this larval stage, these and some other beneficial insects have an especially voracious appetite for pests. Unfortunately for these helpful bugs, they are so ugly as larvae and so unlike their familiar adult forms that unknowing gardeners often squash them.

Other insects do not experience the same degree of transformation; instead they go through a gradual metamorphosis. These insects are called nymphs in their immature stage, when they look like smaller versions of their adult forms; mantids are examples of such insects.