The caddisflies comprise a medium sized order of winged, holometabolous insects.

The larvae of caddisflies (with few exceptions) live in fresh water, and most of them build portable or fixed protective dwellings (cases) out of sand, twigs, plant fragments and other available materials tied together with silk. The imagines (adults) are terrestrial, and have two pairs of hairy wings which are folded in a roof-like manner over the abdomen at rest. The caddisflies are the sister group to the lepidopterans (butterflies and moths), and adult caddisflies have a strong resemblance to the more basal moth groups.