The American Idia moth has a wingspan of .75 to 1.25 inches. The forewing is pale gray with squiggly black lines that form black patches on the costa. The orbicular and reniform spots are rusty brown. The hindwing is gray with 3 black lines. The caterpillar is brown with some dark brown spots and sparse white hairs on the lower sides. The head is black. The proleg on abdominal segment 3 is missing.