Royal Walnut Moth
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 The adult moth is the largest moth by mass in latitudes north of Mexico, as are the spectacular larva and the substantial pupa.
The life cycle of the moth is typical of the Saturniidae species, and typical of the Ceratocampinae. It burrows into the ground to pupate in an earthen chamber, rather than spinning a cocoon. source