What's the difference between moths and butterflies?

Is this winged creature a butterfly or a moth? See more insect pictures.
©iStockphoto/Valeriy Kirsanov

Suppose a beautiful insect lands on your arm late one afternoon while you're relaxing outside. You can see six legs and two antennae coming from on its narrow body, and it has four wide, sweeping, green wings with delicate red and yellow accents. If you carefully touch a wing, a little bit of powder comes off on your finger. It's obvious to you that this insect either a butterfly or a moth -- but which is it?

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Butterflies and moths have a lot in common. They're both part of the scientific order Lepidoptera, meaning scale winged. The name comes from those powdery scales that come off when they're touched. But butterflies and moths have more similarities than just their dusty wings. Both insects start their lives as hungry caterpillars before transforming themselves completely into their flying adult forms. They both eat nectar from flowers, and they supplement their diet with other liquids, like mineral-filled standing water and the juice from rotting fruit.

The difference between butterflies and moths is a lot like the difference between frogs and toads. There are some rules of thumb you can follow to tell them apart, but there are also exceptions to those rules. Next, we'll look at exactly what makes a butterfly different from the moth and what clubs and feathers have to do with it.