Hickory Horned Devil: Dragon Or Caterpillar?

By Doug Pifer

Since high school days I’ve been known as the bucket guy. Folks find some kind of creature and bring it to me, usually in a bucket, to identify. Sometimes I know what it is and sometimes I don’t, but I always enjoy trying to solve the mystery.

My most memorable bucket was a blue plastic one presented to me by Gale Bowman Harlow at her farm on Crum’s Church Road in Clarke County, Va. Accompanied by a dozen young artists and counselors, Gale held the bucket out to me and announced that Disney had arrived at Opus Oaks junior art camp.  Crawling around in the blue bucket was a truly magnificent caterpillar. What was it?

This time I was sure. To a naturalist this was the Holy Grail. Most of us know all about it but few of us ever see one alive. It was a hickory horned devil.

A junior camper discovered it first thing in the morning as it crawled in the grass under a big black walnut tree. An adult counselor had enticed the creature onto a stick and into the bucket to keep it from harm.

Bravely I reached for the devil and placed it on my arm, to horrified gasps from my audience. The creature was the size of a hot dog, but I knew it was completely harmless. Yet it grasped my arm with powerful legs in a grip that made me flinch.

Backwards from the front of its body curved five pairs of blazing orange, dragon-like horns, each studded and tipped with black spines. Behind its tiny head between the curving horns leered two pairs of black spots, like enormous eyes!  The skin was a brilliant combination of bright green and turquoise blue. Each segment sported two pairs of shiny black, studded spines.

Horned devils spend their days hanging upside down from the branches of walnut, hickory, persimmon, sumac, lilac, or sweet gum trees. As they feed their bright colors make them nearly invisible. The outlandish display of adornments is a devil’s only defense against a bird or mammal that would relish such a big, nutritious morsel.

Naturalists have learned to locate hickory horned devils by finding their droppings under the trees. Devil poop, balls of digested leaves called frass, is textured like miniature hand grenades, about the size of dried peas.

In late summer the devil crawls out of the trees to pupate in loose soil without spinning a cocoon. What emerges is called a royal walnut moth, a dramatic night flyer whose fuzzy orange body is the size of a packet of nickels. The veins of its soft blue gray wings are traced with bright orange and overlaid with fawn-like, creamy spots. You might find one of these perched near the window of a gas station, resting from flying around the lights.