Morpho menelaus wing close up. Morpho wings have no blue pigment, and gain their iridescent colour by reflecting incident light repeatedly at successive layers leading to interference effects. The colours stay suprisingly true regardless of angle of view, probably due to highly uniform tetrahedral scale arrangements. Their underwings are brown with eye spots. Morphos are found in Central and South America. Their wings are used in jewelry and the butterflies are prized entomological and display specimens. The structural nature of the blue means it will not fade if kept clean.