What's That Bug? does not endorse extermination

LARGE Caterpillar found in Ozark, Missouri
Location: Ozark, MO (southwest Missouri)
July 21, 2011 10:39 pm
Can you identify this large dark/bronze/copper/brown colored caterpillar? We found it in early July in my flower bed, not far from my Walnut tree. It was about 3 inches long. We saw no others before or since. I’ve lived here 12 years and have never seen such a creature! In the photos, you can see the ”horns” and the tufts of ”hair”. It has a black ”band” across it’s head. Also, what Moth or Butterfly will it become?
Signature: ~Susi M.

Hickory Horned Devil

Hi Susi,
Your large caterpillar, a Hickory Horned Devil, will nearly double in size and change color from brown to aqua-green as it progresses through metamorphosis to become the largest North American Caterpillar.  We received our first Hickory Horned Devil sighting of 2011 a few weeks back and we have been getting numerous reports of the adult Royal Walnut Moths this summer, which makes us believe that there will be even more mature caterpillar sightings in August and September.  Folks don’t usually notice the Hickory Horned Devil until the caterpillars have grown to full size and  then climb from the trees to crawl upon the ground in search of a suitable location to dig beneath the surface where pupation occurs.  Walnut and Hickory, which provide the common names for the moth and its caterpillar, are just a few of the trees that serve as a host for the caterpillar.  Others include sumac and persimmon.  The adult Royal Walnut Moth, like other Giant Silk Moths, does not feed as an adult.  Adults live long enough to mate and lay eggs.  BugGuide has a nice series of images of various instars of the Hickory Horned Devil.  The fully grown caterpillar with its bright coloration and striking horns is often likened to a Chinese dragon.

Daniel,
Thank you SO much for replying so QUICKLY!! We found a very large moth last night fluttering against a rock wall here, put it in a jar and by morning it had laid numerous eggs! We think it may be the Royal Walnut Moth from our Hickory Horned Devil Caterpillar you identified! I will take photos and send them to you to be sure. It doesn’t look exactly like the other Royal Walnut Moths I’ve seen photos of at the Bug Guide link you sent me, but it may be one of them. I’ve lived here many years and have never seen these caterpillars near any walnut trees in this area. Where are they normally from? And why would they be appearing here all of a sudden? Thanks again.
~Susi Meredith
Ozark, Missouri

Hi again Susi,
Just because you didn’t notice any Hickory Horned Devils does not mean they were not present.  Even though they are large, they could easily escape notice in a large tree.  Since the adult moths fly, they are capable of increasing their range to places where there is available food.  Perhaps you are part of a natural range expansion.

What's That Bug? does not endorse extermination

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