Difference between a butterfly and a moth

The Difference between butterflies and moths is subtle, but there are a few ways to recognise the difference between a butterfly and a moth, both insects of the order Lepidoptera. Of course, no rule is perfect, but as a general rule the following conditions apply. The reader should understand that the designations "butterfly" and "moth," while indispensable for laypersons and even for scientists who specialize in the Lepidoptera, are popular, not scientific, terms for these familiar insects. That is, "butterfly" and "moth" are not natural classifications based on differences in morphology or behavior. Nevertheless, exceptions to the following rules are so few and far between that for almost all purposes the terms "butterfly" and "moth" are acceptable. Only bear in mind that there are many brightly-colored day-flying species of moths, for example, and that there is even one species of butterfly, Pseudopontia paradoxa from the forests of central Africa, whose thread-like antennae lack the distinctive clubbed ends that identify butterflies. Okay, here are the rules:

• The most obvious difference is in the feelers, or antennae. A butterfly has a thin straight pair of antennae which ends in a small club, while moths usually have large feathered antennae in the males that help them to sense female pheremones in the air and to steer themselves when they fly in the darkness and thin, straight, unclubbed antennae in the females. Not all moths have the feathering on their antennae, but they all lack the clubbed end of a butterfly.
• Moths are virtually all nocturnal or crepuscular[?] (active at dawn and dusk), while there are no nocturnal butterflies.
• Another major difference is in their pupa[?] or metamorphosis stage when they change from caterpillar to adult insect. A moth spins a cocoon around its pupa to protect and conceal itself, while butterflies metamorphose inside a hardened shell called a chrysalis[?].
• Many, but not all, butterflies have bright colourful patterns on their wings. Moths' wings are usually plain brown/grey/white/black, often with obscuring patterns of zigzags or swirls, to help camouflage them while they are resting in the daytime.
• Moths rest with their wings spread out to their sides. Butterflies often (but not always) fold their wings above their backs when they are perched.
• Moths tend to have very fat hairy or furry appearing bodies, while butterflies are slighter and smoother.

Polythemus moth - note the feathered antennae and fat furry body Please click on the image to see an enlarged version for more detail.

A Kamehameha butterfly - not the best example in the world, but note the clubbed antennae and slender body Please click on the image to see an enlarged version for more detail.

A monarch butterfly demonstrating the common butterfly resting position Please click on the image to see an enlarged version for more detail.