Butterflies and Moths (Lepidoptera)
This large, familiar, primarily terrestrial, insect order does have some (moth) species with aquatic larvae which are referred to as "aquatic caterpillars." About 50 species in North America can be considered aquatic, and all are herbivores. Most feed in or on specific aquatic host plants, often in lentic habitats. Others make silken retreats on rocks in stream habitats and feed on algae. Aquatic caterpillars are found infrequently in Iowa streams. They can be distinguished from other aquatic larvae by their 3 pairs of thoracic legs and the abdominal prolegs ringed with circles of tiny hooks (crochets). The name Lepidoptera, derived from the Greek words "lepido" for scale and " ptera" for wings, refers to the flattened hairs (scales) that cover the body and wings of most adults.