The image shows some scales that cover the surface of the wing of the podalirium, as of other lepidoptera. The image was taken under a scanning electron microscope (SEM).
<a href="//commons.wikimedia.org/wiki/User:Mtbusca" title="User:Mtbusca">Maria Teresa Buscaglia e Giovanna Canu</a>
CC BY 4.0
<span class="int-own-work" lang="en">Own work</span>