Caterpillars in Your Yard and Garden
Royal moths and silkworm moths
Hickory horned devil caterpillars (Citheronia regalis) are present from July to October. They produce two generations per year.
This fierce-looking caterpillar is the immature stage of the regal moth. Full-grown larvae are dull green and can reach lengths of 4 to 5 inches. On the thoracic segments behind the head are long, stout, orange and black spines or "horns." The longest of these horns are found on the second and third thoracic segments. Six smaller black spines are found on each abdominal segment. Host plants include hickory, walnut, butternut, sumac, persimmon, sweetgum, ash and sycamore.
About the family
Royal moths and silkworm moths of the Saturniidae family include many of the largest and most colorful moths in North America and the world. These large caterpillar species are usually not considered pests. Although a single individual can consume relatively large amounts of foliage, their numbers rarely reach levels that would warrant control. But there are a few species that can do significant damage to many forest tree species. Upon completing their larval development, most saturniid caterpillars will pupate in large, tough silken cocoons usually attached to twigs or leaves or found on the ground. Many species have only one generation per year.