Eyespot of butterfly. Macrophotograph of the wing of the apollo butterfly Parnassius apollo, showing an eyespot. Small overlapping scales produce the colouration and patterning of the wings. Here, a black and red, rounded eyespot is seen, occurring on the hindwing. The eyespot is a mimicry device. It resembles the eye of a larger animal, and it serves to startle predators when the wings are suddenly flashed open. Hindwing eyespots are otherwise hidden by the forewings. Parnassius apollo is a white and grey coloured butterfly, widely distributed in Europe and eastwards to central Asia. Adults appear in June to August.