Inchworm and the Ruler

Guest article by Henry Mitchell

Unannounced Visitor

On a warm day in July 2006, as I sat working at my desk near an open door, I became aware of a visitor — a hyperactively inching inchworm! First I coaxed it onto my arm, then into my hand, all the while attempting to align it with a ruler, while my sons David and Jonathan assisted in getting quick photos.

Elusive Photo Model

The upper left photo shows the inchworm at rest on my arm alongside the ruler, proving it was just over an inch long. Then, as it humped along, its motions were so quick and spastic that the camera could not capture the images without motion blur. At lower left the inchworm is exhibiting its typical inching motion in the palm of my hand, arching up in order to bring its back appendages forward. (It has no legs in the center of its body, thus it must perform its characteristic looping, jerky movements.)

Inches to Centimeters

At right the inchworm is moving along on the surface of the ruler itself. Having chosen the opposing side of the measuring device, it appears the inchworm is converting to centimeters — about 2.5 of them!

An Old Superstition

According to author/editor/journalist Henry Hurt, there is an old superstition that if an inchworm is found on your person, he is measuring you for a coffin: “All my life, I've heard you'd better call your preacher and get Right when an inchworm lands on you and starts measuring. It happened to me once when I was loafing in a hammock. Whew!”

The Process of Becoming…

There are many species of inchworms; all are larvae of moths of the family Geometridae (see related article).

(Also see this photograph in larger format.)