What is the difference between a butterfly and moth?

The difference usually quoted in the text books is that butterflies have knobbed antenae and moths feathery ones.

. However one group of day-flying moths, the burnet moths, has antennae that look pretty much like as if they are knobbed.

One difference that is useful is the difference in the way in which they hold their wings when resting. Moths generally fold their wings down and butterflies close them over their backs. However there are execptions in both butterflies and moths.

The best difference is that moths have a device called a frenulum which links each pair of wings togther and butteflies do not.

This works for almost everything. Unfortunately the male of the Australian Regent Skipper butterfly is an exception being the only butterfly with a frenulum.