What is "eyespots"

Usage examples of "eyespots".

The length of her middle finger, its thorax black, yellow-striped, its lower wings elongated into frilled arabesques like those of a festoon, deep yellow, charcoal black, with indigo eyespots, its upper wings a chiaroscuro of black and white stripes.

The black pigment of the eyespots is preserved better than anything else.