Known in scientific circles as Lepidoptera, butterflies and moths, while closely related, display wildly different characteristics. At a glance we can usually tell a butterfly from a moth by whether it flies during the day or the night. Butterflies are day flyers, and moths are most often nocturnal. Look inside for more details about and gorgeous photos of swallowtail butterflies; blue, copper, and hairstreak butterflies; burnet moths; and atlas, silk, and hawkmoths. See their remarkable metamorphosis process up close: the egg, the larval or caterpillar stage, the pupal stage, and finally the adult the full-grown, high-flying insect.