Insects that go through three stages of change in their life cycle have an incomplete metamorphosis while complete metamorphosis has four stages.
The first stage of incomplete metamorphosis is the egg. During this time, the insect will hatch into a form called a nymph.
The nymph is basically a small version of the adult insect. This is very similar to how a child looks like his or her parents. Nymphs usually have a thin exoskeleton and no wings. They eat the same food as their parents and live in the same place. As insect nymphs grow larger, their exoskeleton becomes too tight and they must replace it.
Once a nymph outgrows its exoskeleton it will go through a process called molting, in which it leaves the old “skin” or exoskeleton behind. The new “skin” will harden and become the new exoskeleton. This will happen many times until the insect finally becomes the size of an adult.
Insects that have an incomplete metamorphosis life cycle include true bugs, grasshoppers, cockroaches, termites, praying mantises, crickets, and lice.
Grasshopper nymph and adult
These two lubber grasshoppers are examples of a nymph and adult form. Can you tell which one is the nymph and which is the adult? Images by Bob Peterson and Fredlyfish4 via Wikimedia Commons.