Caterpillars (Lepidoptera) are the most common order in the class Insecta. The color is beautiful, and the adult body limbs and wings are covered with scales and hairs, so the two pairs of wings are scale wings, and the forewings are larger than the hind wings; siphon-type mouthparts (the primitive small-winged moths have well-developed upper jaws and are chewing); the antennae are filamentous. , double ctenoid, ctenoid, club-like and other types; compound eyes are well developed, with 2 or no ocelli. The larvae are worm-like, with 3 pairs of thoracic legs, and mostly 5 pairs of abdominal and caudal legs. There are setae on the larvae. The arrangement and naming of the setae are called trichomes, which is of great significance in classification. There are about 112,000 species, including moths and butterflies. Some can be used as bait and feed fish.
