ID'ed by smaller size than Monarch, white spots at outer leading edge of fore wings, and black stripe parallel to wing edge at trailing edgeof hind wings. "The viceroy and monarch were once thought to exhibit Batesian mimicry where a harmless species mimics a toxic species. Studies conducted in the early 1990's suggest that the viceroy and the monarch are actually examples of Mullerian mimicry where two equally toxic species mimic each other to the benefit of each." - from Nature Works on the NHPTV website.