Covering the wings are thousands of colourful scales, together with many hairs (setae).
The name Lepidoptera (which includes butterflies and moths) means "scale wing" in Greek. These wing scales are tiny overlapping pieces of chitin on a butterfly or moth wing. The scales are outgrowths of the body wall and are modified, plate-like setae (hairs).
The front and back of the wings usually have different patterns.