Regal Moth (Hickory Horned Devil)

Citheronia regalis — the regal moth — is one of the largest moths in North America and the species whose caterpillar (the legendary 'HICKORY HORNED DEVIL') is one of the most-photographed insects in southeastern US natural history. The species is widespread across the eastern US from southern New England south through the southeastern US to northern Florida and west to Texas. Adults are 9-13 cm wingspan, with grayish-brown forewings marked by yellow and orange spots, orange hindwings with yellow markings, and a fat olive-orange body. Adults are nocturnal, do not feed (the digestive system is non-functional in adults — they live 1-2 weeks on stored larval body fat), and the females release pheromones to attract males. The species' MOST FAMOUS form is not the adult moth but the LARVA — the legendary 'HICKORY HORNED DEVIL' — the LARGEST CATERPILLAR IN NORTH AMERICA. Late-instar caterpillars reach 13-15 cm long and are roughly the thickness of an adult human's index finger. The body is bright TURQUOISE-GREEN to blue-green, with a dramatic head capsule bearing TWO PAIRS OF LARGE CURVED BLACK-TIPPED ORANGE HORNS (looking like a miniature dragon's horns) and additional rows of small BLACK SPINES running down the body. The dramatic horned-and-spined morphology is one of the most visually striking caterpillars on Earth and looks unmistakably DANGEROUS — bright warning colors, intimidating horn structures, prominent black spines. The caterpillar is COMPLETELY HARMLESS, however: the horns and spines are NON-VENOMOUS (no urticating stings, no toxin), the caterpillar cannot bite, and contact causes nothing more dangerous than a startled jump from the unprepared finder. The horned-devil appearance is pure VISUAL DEFENSE — bird and small-mammal predators are deterred by the intimidating size and ornament of the caterpillar without any actual chemical or physical defense. Larvae feed on hickory, walnut, sweetgum, sumac, and other deciduous tree species in eastern US forests. The species' annual late-summer caterpillar drop (when fully-grown larvae descend from host trees to pupate underground) is one of the most-anticipated events in southeastern US backyard natural history, and 'I found a hickory horned devil' is a flagship social media event each August across the southeastern US. The species is harmless to humans (despite the appearance) and is a flagship example of intimidating-without-harm defense in caterpillar biology.