Here we look at three of the most common. Inchworms are not actually worms, but the larvae of the Geometrid moth. These larvae are commonly seen floating around, dangling out of the canopies of trees. This behavior marks both a defensive mechanism and a fast method for the caterpillar to leave the tree top.

Why do inch worms inch?

With this type of anatomy, they form a loop as they creep along leaves, said Jerry Goodspeed, Utah State University Extension horticulturist. They look like they are measuring the leaf as they move along, which likely explains how they got the name inch or measuring worm.

Where do inch worms come from?

The name inchworm refers to the larvae of moths in the Geometridae family. Derived from the way in which it moves, its namesake may be somewhat misleading. Although referred to as a “worm,” the larvae of these moths are actually caterpillars.