The Beautiful Hickory Horned Devil Caterpillar
Larva to a Giant Silkmoth known as a Royal Walnut or Regal Moth

by Jana Miller

While many people are avid butterfly watchers I prefer to watch the large moths of the night.

  • Sept 2001 - I was living at the time in Jonesville, Florida at a rental house when my landlord Marty told me about the caterpillar he had at his house. It had fallen into his chicken pen and it was so large a frightening that none of them would get anywhere near it and were making quite a fuss. While normally the chickens would eat anything in sight. No wonder, it was a Hickory Horned Devil. Marty had it inside his house in a jar and offered me to take it home after showing much interest.

    Truly the most fantastic caterpillar I have ever seen.

    So I took the HHD home and set up an aquarium for it to live in while observing it for a short period. I filled it with a base of dirt then fresh large Sycamore leaves (which it eats) and sprayed the leaves daily for the HHD to drink. What I had thought was going to be a temporary visit changed quite soon. Soon after I had the HHD in the aquarium is began to pupate.

  • October 2001 - Not long after the HHD turned into a pupae, I moved about 40 miles West to my newly purchased house in the woods. I decided to take the HHD along after seeing so many large Walnut and Sweet Gum trees that it feeds on, on my property.

  • July 2002 - Many months had passed and the HHD was still a pupae. I had kept it protected from the Winter cold and even added some water to the soil on occasion. I was starting to think it was dead. I kept the pupae in my screened in porch rather than inside the house in case it emerged. Then one day, to my surprise I found the shell of the pupae laying broken above the soil. My first thought was that a raccoon or possum had eaten it although my Leopard Gecko was also on the porch undisturbed.

    The giant silkmoth had finally emerged! It was on the screen of the porch and quite large. I propped the door open so it could fly off when it wanted to. The next night the moth was still there again and an even greater surprise. My moth friend was a female and she now had a friend, a smaller male.

    So now there were two mating Royal Walnut Moths on my front porch. During the night they left. She went to lay her eggs and then die. These moths have no mouth and cannot eat. Their sole purpose is to reproduce by laying eggs on a host tree.


    I was in awe that I had the chance to witness nearly
    the entire life cycle of one of these marvelous creatures.


  • Did you find a Hickory Horned Devil Caterpillar?

    If you come across one of these HHDs the best thing to do is to find one of its host trees and lay it at the base so that it can climb back up. Look for a Walnut, Hickory, Sycamore, or Sweet Gum tree so that it can feed on its leaves. Chances are, it just fell out of the tree and is actually ready to turn into a pupae soon.




September 2001 - Hickory Horned Devil

The leaves of the Sycamore tree that the HHD had already eaten away at. These leaves are so large that the HHD caterpillar actually appears to be small.
This HHD was very active and had such a large body that you could hear it crawling around inside the aquarium as it ate and explored.


In my hand, for a better representation of the HHD's size.

This particular HHD was approx. 5 inches long and nearly 1 inch wide at its thickest section. As frightening as it may appear the HHD is completely harmless.
October 2001 - Hickory Horned Devil Pupae

The HHD pupae.
Very large compared to other pupae.
July 2002 - Royal Walnut or Regal Moth


The striking Royal Walnut or Regal moths. The larger female is to the left. An approx. wingspan of 5 to 6 inches.

The soft hair-like scales on these moths helps them to be active on cold nights. This scaling insulates the moths' bodies and is warmed by muscles shivering prior to flight.


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