Moths and butterflies both belong to the order Lepidoptera, but there are numerous physical and behavioral differences between the two insect types.
On the behavioral side, moths are nocturnal and butterflies are diurnal (active during the day). While at rest, butterflies usually fold their wings back, while moths flatten their wings against their bodies or spread them out in a "jet plane" position.
Their pupal stage (between the larva and adult stages) is slightly different, too. Here, moths make cocoons that are wrapped in silk coverings. Butterflies, on the other hand, form chrysalises, which are hard, smooth and silkless.
Physical differences abound. Butterfly antennae are thin with club-shaped tips, compared with the feathery or comb-like antennae of moths. Moths are stout and fuzzy; butterflies are slender and smooth.
And wing colorations between the insect types are generally polar opposites, with butterflies sporting more vibrant colors. Additionally, moth wings, unlike butterfly wings, have a structure called a frenulum, which joins the forewing to the hind wing.
Though these various traits usually distinguish a butterfly from a moth, there are numerous exceptions to these rules. The Madagascan sunset moth, for example, is brightly colored and active during the day.