John Borden, age 10, of Rockford, Illinois, for his question:

What makes a butterfly's pretty colors?

Many of Andy's young readers love big words and here is a chance to meet a big beauty. Butterflies belong in the insect class called Lepidoptera. And this fancy science word gives us a hint about the answer for today's question. It means scaly wings. We know that fish have scaly skins, but we need a strong magnifying glass to see the scales on a butterfly's wings.

When a bit of the wing is enlarged under a microscope, the scales look like cities of fairy buildings made of clear, shiny glass. The beautiful colors we see on the butterfly seem to have disappeared. But remember how a sunbeam shines through a pointed glass prism. The clear sunbeam changes into ribbons of rainbow colors. The glassy scales on a butterfly's wings must wait for just such a sunbeam. Then the little fairy eities steal some of its hidden colors and make others shine out in patches of blue and green, velvety yellow and other favorite butterfly colors.