Our insect of the week for August 4, 2025, is Catocala ilia (Cramer, 1776) [LEPIDOPTERA: Erebidae]. The common name is beloved underwing. Adults fly from June through September. Larvae feed on various species of oak. Some larvae grow to roughly 3 inches in length.

This species is found in the eastern United States and southern Canada. A subspecies is known from California and Arizona. Adult moths have a white spot on each forewing (which can be variable in size and detail). Two variant forms are shown in these photos with this post. The featured image has the more common and prominent white spots. The image below has more diffuse white spots. There is a fair amount of variation in hind wing patterns and coloration as well.

Underwing moths get their name because their brightly colored hind wings are usually hidden by their forewings (which often resemble tree bark). When disturbed, they open their forewings to reveal the bright colors which may deter predators. Caterpillars are camouflaged to resemble twigs. They may also flip back and forth and turn upside down when disturbed. The underside is often pink colored with large black spots. This behavior and coloration may also confuse predators.

Photos of the adult were taken by our former member, Frank Hitchell from specimens found in Peoria County, Illinois.