The regal moth (Citheronia regalis), also called the royal walnut moth, is a North American moth in the saturniidae family. The caterpillars are called hickory horned devils. The adult (Imago) has a wingspan of 3.75-6.1 in (9.5-15.5 cm).
Citheronia regalis is considered a common species in the Deep South, becoming rarer and more sporadic northward. It is found throughout the deciduous forests United States from Missouri to Massachusetts and southward from Texas to central Florida. Historically recorded throughout New England, the species suffered a decline in the Atlantic Northeast during the mid-20th century.
Excluding sparse contemporary records from New York, Citheronia regalis achieves range stability in the mid Atlantic states and southern Appalachia, beginning from southern New Jersey west throughout the Ohio Valley, the edge of the Great Plains states and south to East Texas. source