Caterpillars are the larvae, or young, of butterflies and moths. The word comes from the Latin catta pilosa, meaning "hairy cat." Although it is easy to recognize the hairy variety, many caterpillars with bare skins are often mistaken for worms, such as the cabbageworm and armyworm.

    The head of a caterpillar is followed by 12 or 13 segments. Like all insects, caterpillars have three pairs of permanent legs, one pair on each of the first three segments directly behind the head. These legs are usually hard and jointed. At their tips are tiny claws, but in some caterpillars these are not developed. The caterpillar also has two to five pairs of soft, thick legs that support the rest of its long body. These disappear when it changes into a moth or butterfly. A caterpillar has six tiny beadlike eyes on each side of the head, just above the strong upper jaws. It breathes through nine small openings on each side of its body. These are called tracheae. It also has short antennae. Caterpillars vary in size from less than an inch to a few inches.

    Caterpillars are the prey of many birds and insects. To avoid attacks, they have natural protections. Some caterpillars are colored to blend into their surroundings. Others have showy dots r stripes on their bodies that make them look fierce or very large. A few give off unpleasant smells, and a small number grow poisonous hair.

    The change that a caterpillar undergoes to turn into a butterfly or a moth is called metamorphosis. Some caterpillars may take only a few days to make this change. Most, however, stay as caterpillars throughout the warm season. A small number may live as long as four years in the caterpillar form before they change.

What is tracheae?