The forewings of both sexes are white with wavy dark bands across. The underwings are brownish-gray. However a color of moths vary much, from white to dark forms.
Female forewing (wing span about 45-55 mm) is white, with black spots and wavy lines with sharp points; the hindwing is greyish brown, minute hairs on edge white with brown spots. The head is white; thorax white marked with black; abdomen pink with brown transverse bands, more distinct in female; antennae of male feather-like, of female weakly so. Male forewing (wing span about 35-45 mm) brown with dark brown to black wavy lines with sharp points, hindwing is uniformly light brown; a melanic grey-brown form of the male is also known to occur.
Source:
http://www.inspection.gc.ca/english/sci/surv/data/lymmone.shtml
