The red-spotted purple has a wingspan of three to four inches. The upperside of the wings is dark blue-black to blue-green. The underside of the forewing has two red-orange bars while the underside of the hindwing has three red-orange spots near the body and a row of red-orange spots near the outer edge of the wing. The caterpillar is gray-brown and white with a hump toward the front end.
The red-spotted purple may be found statewide in Illinois. Its caterpillar eats the leaves of wild black cherry, poplars, aspens, black oak and other plants. The larva overwinters in a shelter made of leaves.