|More Lepidoptera Information
Inchworms, the small caterpillars made famous in songs, cartoons and toys, belong to the Geometridae family of moths.
The movement is a result of their leg structure. A quick glance at the top picture shows a caterpillar with three pairs of true legs up front (right hand side of the picture) and two pairs of prolegs (back legs on the left and side of the picture).
The majority of caterpillar species have 3 sets of legs (true legs) at the front of the body, and five set of legs (prolegs) at the back of the body. The lack of additional prolegs causes the caterpillar to inch along.
Around twelve hundred different Geometridae species can be found in the United States. Many have dull, brown wings complimented by a line pattern. Many of the caterpillars are small and green, although as the picture shows, they can also be brown with a pattern.
© 2010 Patricia A. Michaels