How can I tell a butterfly from a moth?

Butterflies and moths are related in many ways. Butterflies are generally brightly-colored while moths are generally drab, though they are many dramatic exceptions to this.

Almost all butterflies are active during the day, and most (but not all) moths are active at night. The easiest way to tell the difference is by their antennae. Butterfly antennae are shaped somewhat like a golf club, with a long shaft. Most moths have either simple filaments tapering to a point, or complicated affairs with many cross-filaments.