Butterflies have scale-covered wings. The coloration is created by minuscule scales. These scales are pigmented with melanins that give them blacks and browns, but also blues, greens, reds and iridescence.
Do an internet search with them so that they can find the information they are looking for and they will be able to print it out so that they can study it as a team and draw conclussion on exactly what the things are called that they are looking for and the best ways on how to do it.
