Butterflies and moths are members of the order Lepidoptera. The lepidos is Greek for scales and the ptera is Greek for wings. It is this distinguishing feature that separates them from all other insects. There are about 120,000 species of Lepidoptera. The order is divided into three suborders: Jugatae, Frenatae (moths) and Rhopalocera (butterflies and skippers).
The life cycle of Lepidoptera involves four stages: the egg, larva, pupa and winged adult. All Lepidoptera larvae are called caterpillars. As they grow they go through several molts, getting larger with each molt. The body of both the caterpillar and the adult have three segments: head, thorax and abdomen. During the pupal stage Lepidoptera goes through a complete metamorphosis. The pupal stage can last from a few days to several months.
When the adult butterfly or moth emerges it now has two segmented antennae, two compound eyes and a long sucking tube called a proboscis that it uses to feed on nectar and other fluids. The thorax now has a pair of five-jointed legs and two pairs of wings.