- Butterflies have straight and club-like antennae, moths have "plumose" or feather-like.
- Butterflies make a chrysalis when they pupate, moths make a silk cocoon.
- Butterflies are diurnal (active during the day), moths are nocturnal (active at night).
- Butterflies rest with wings open, moths rest with wings closed.
- Butterfly always have a feeding mechanism (called a proboscis), whereas a moth may not.
Update: Below I have added a link from a post by the folks at the Tales from the Butterfly Garden blog on the same topic: