Adult American snouts have greatly elongated labial palps (mouthparts) that make them seem to have long “noses.” There is only one species of snout butterfly in Missouri. Forewings are elongated with squared-off wingtips. The dorsal wing pattern is orange with wide dark borders with white spots. Seen from below on perched specimens, the wings usually only show mottled brown and gray, though the forewings look roughly the same on both sides. When perched on a twig, with only the gray showing, a snout butterfly is virtually invisible.
Larvae are dark green with yellow stripes along the back and sides. The thorax portion is enlarged, with two black tubercles.