Caterpillarlike larvae of insects found openly on foliage can generally be distinguished by the number and location of prolegs (leglike appendages, or fleshy stubs) on the abdomen and whether true legs are present. Larvae of openly feeding sawflies (wasps, Hymenoptera) have pairs of prolegs on six or more abdominal segments. Caterpillars (butterfly and moth larvae, Lepidoptera) have proleg pairs on five or fewer abdominal segments. Larvae of leaf beetles (Coleoptera: Chrysomelidae) have no prolegs. Larvae of flies (Diptera) lack true legs, as illustrated here by a predatory syrphid, and have fleshy protuberances on their abdomen or on both their abdomen and thorax. Credit: David Kidd. Adapted by UC IPM.
