This set of four stamps shows butterflies and moths from different geographic areas of the United States. Butterflies and moths are insects that account for more than 100,000 species worldwide. They are in the insect order Lepidoptera, which in Latin refers to the scales found on their wings. Colored with pigments or color-forming structures, the scales form distinctive color patterns. This is particularly seen in butterflies. The most important and widely known families are primitive moths, advanced moths, most advanced moths, skippers, and butterflies.