Mourningcloaks are a fairly large butterfly with a wing span of 6-10 cm, or 2 1/2 to 4 inches. Their upperside is purple-black, or brown-black, with a wide, bright yellow border on outer edges.There is a row of iridescent blue spots at the inner edge of the yellow border. This color pattern.makes them easy to identify. The underside of the wings is dark brown with lighter brown edges. Mourningcloaks have short projections, or points, on their wings.