Types of Caterpillars


Butterflies and moths go through "complete metamorphosis" – that is, they have four distinct developmental stages - egg, larva, pupa and adult. Caterpillars are the larval stage and is essentially an “eating machine” that must consume large amounts of their preferred larval food, which is stored as fat that energizes the adult stage.


Caterpillars are often camouflaged; however, many caterpillars have brilliant colors and patterns that usually serve to warn or scare away predators. Most caterpillars are totally harmless, but a few species are protected from predators by stinging spines or hairs located on their body, plus some have a ferocious and intimidating appearance. Examples of caterpillars that cause injury are the puss caterpillar, the buck moth caterpillar, the Io moth caterpillar and the saddleback caterpillar. A good “rule of thumb” is never pick up a caterpillar that has spines on its legs or other parts of its body.

A few of the more easily recognizable caterpillars and the damage they cause include:

Bagworm caterpillars

These caterpillars are usually seen on ornamental cedar trees and bushes. As the name implies, they construct a silk bag that is covered by plant debris. In some cases, bagworms so heavily infest a host plant that it dies.

Inchworm caterpillars

Inchworms are leaf feeders that have an unusual way of moving around. In order to move, inchworms move their rear legs forward which creates a loop in the middle of their body and then straighten out the loop which causes the front legs to move forward.

Monarch butterfly caterpillars

Monarch caterpillars are ornately colored with white, yellow and black transverse bands, are large and eat milkweed plants. These caterpillars grow to be about 2 inches long before completion of their caterpillar stage.

Webworm caterpillars

These caterpillars live inside a loosely constructed, thick web that encloses the leaves of a tree.

Fabric infesting caterpillars

The webbing clothes moth consume fabric and can be recognized by construction of silk tunnels or mats mixed with their feces and fragments of the infested cloth.

Casemaking clothes moth caterpillars live in a small, silken case which they carry with them as they move to feed on parts of cloth they infest.

Stored food product infesting caterpillars

One of the more commonly encountered stored product food contaminating moth is the Indian meal moth caterpillar. This caterpillar produces silk webbing on the top surface of foods it infests.


While the appearance of various species of caterpillars and moths is extremely variable, one simplified characteristic used to differentiate caterpillars is moth caterpillars are usually described as being somewhat fuzzy, while no butterflies are considered fuzzy.

Both moth and butterfly larvae have a cylinder-shaped body consisting of three body segments - the head, thorax and abdomen. Caterpillars have 1 head segment, 3 thoracic segments and 10 abdominal segments. The head has a short pair of antennae and several simple eyes, the thorax has a pair of legs on each segment and the abdomen has a pair of prolegs on segments 3-6 and 10.