Lepidoptera An order of insects comprising the butterflies and moths, found mainly in tropical regions. Adults possess two pairs of membranous wings, often brightly coloured and usually coupled together. The wings, body, and legs are covered with minute scales. Adult mouthparts are generally modified to form a long proboscis for sucking nectar, fruit juices, etc. Butterflies are typically small-bodied, active during daylight, and rest with their wings folded vertically; moths have larger bodies, are nocturnal, and rest with their wings in various positions. The larvae (caterpillars) have a prominent head and a segmented wormlike body, most segments bearing a pair of legs. They chew leaves and stems, sometimes causing considerable damage to crop plants. The larvae undergo metamorphosis via a pupa (chrysalis) to the adult form. In some groups, the pupa is enclosed in a cocoon of silk derived from silk glands (modified salivary glands); others use leaves, etc. to build a cocoon.

Lepidoptera (moths and butterflies; class Insecta, subclass Pterygota) Major order of insects, characterized by wings with overlapping scales. The wing-span ranges from less than 5 mm to about 250 mm. Adults generally have a sucking proboscis; rarely they have chewing mouth-parts (Micropterigidae). The larvae have chewing mouth-parts and are nearly always plant feeders. The pupae generally lack functional mandibles. Lepidoptera are endopterygotes, with an estimated 165 000 species.

lepidoptera order of insects with scale-covered wings. XVIII. modL., f. Gr. lepis, lepído- scale + pterón wing (cf.FEATHER).