any of a group of moths in the family Saturniidae (order Lepidoptera) that are large and brightly coloured and occur only in the New World.

The ferocious-looking but harmless hickory horned devil caterpillar (larva of the royal walnut moth, Citheronia regalis) has a black-spined, green body and black-tipped red spines behind its head. It eats principally walnut, hickory, and persimmon leaves. The adult has yellow-spotted, olive-gray forewings with red veins and reddish-orange hindwings with yellow markings. The imperial moth (Eacles imperialis) has yellow wings and body with purple to brown markings. The green body of the larva has a sparse covering of long white hairs, yellow horns, and a brown head. Striped Anisota larvae (e.g., the green-striped mapleworm, A. rubicunda; the pink-striped oakworm, A. virginiensis; and the orange-striped oakworm, A. senatoria) may at times cause much damage to maple, oak, and box elder trees.

The regal moths are sometimes classified in their own family, called Citheroniidae.