One of the big differences in butterflies and moths is their antennae. A butterfly has antennae with a club on the end. A fat part. ALL butterflies have that. A moths antennae are either thin or it can be wide and feathery. Also, moths usually have fatter bodies. You see butterflies mostly during the day, and moths at night. Also, in most cases, butterflies rest with their wings in an upright position. Moths rest with their wings out to their sides. Here's some impressive and common North American moths. You may have never seen one. You have to know where to look!