Butterfly wing. Close-up of an eyespot on the wing of a butterfly, species Salamis aethiops (family: Nymphalidae). The structure of a butterfly wing is like a roof, with coloured scales corresponding to the overlapping tiles. The colour of a butterfly's wing is determined by pigmentation of the scales and also by diffraction of light off the surface of each scale. Eyespots mimic the eyes of a larger animal and serve to startle predators when the wings are suddenly flashed open. This butterfly belongs to the family of brush-footed or four- footed butterflies and lives in equatorial Africa.