A fifth instar caterpillar of the Splendid Royal Moth (Citheronia splendens) feeding on Wild Cotton (Gossypium thurberi) in the Santa Rita Mountains of southeastern Arizona.
The brightly colored adult moths appear in July and August, and caterpillars can be observed in September.
The full-grown caterpillars can be very conspicuous on their hostplants, reaching a length of nearly 7 inches.