A medium-sized (4.6-6.0 cm wingspan) moth with dark forewings and red and black hindwings. The forewings are a smooth, dark rich chocolate and grey brown with several fine erratic horizontal lines. A narrow patch along the costa at the apex is lighter brown. The hindwings are deep red-orange, almost scarlet, and are crossed by a complete black median line and a wider black terminal band. The basal area is covered with long black hairs, and the fringes are mostly dark. Both the sexes are similar. The antennae are filiform. Ultronia cannot be mistaken for any other Alberta Catocala.