Macroinvertebrate Photo Gallery
Macroinvertebrates are animals without a backbone that can be seen with the naked eye. These bottom-dwelling animals include crustaceans and worms but most are aquatic insects. Beetles, caddisflies, stoneflies, mayflies, hellgrammites, dragonflies, true flies, and some moths are among the groups of insects represented in streams. Macroinvertebrates are an important link in the food web between the producers (leaves, algae) and higher consumers such as fish.
Need to identify an aquatic macroinvertebrate you found in a stream? Use our dichotomous key.

Visit the Stroud Center’s Leaf Pack Network® website to learn about a simple experiment that uses tree leaves and aquatic insects to determine the health of your local stream.
Click on images to enlarge. All photos by David H. Funk.
Acari (water mites) Amphipoda (scuds) Ancylidae (limpets) Baetidae (small minnow mayflies) Bivalvia (clams) Blepharoceridae (netwinged midges) Brachycentridae (brachycentrid caddisflies) Caenidae (small squaregill mayflies) Ceratopogonidae (biting midges) Chironomidae (midges) Chloroperlidae (green stoneflies) Coenagrionidae (narrowinged damselflies) Decapoda (crayfish) Elmidae (riffle beetles) Empididae (aquatic dance flies) Ephemerellidae (spiny crawler mayflies) Ephemeridae (common burrower mayflies) Ephemeroptera (unidentified mayflies) Gastropoda (snails) Glossosomatidae (saddlecase caddisflies) Gomphidae (clubtail dragonflies) Helicopsychidae (snailcase caddisflies) Heptageniidae (flatheaded mayflies) Hirudinea (leeches) Hydrophilidae (water scavenger beetles) Hydropsychidae (common netspinner caddisflies) Hydroptilidae (micro caddisflies) Isopoda (aquatic sowbugs) Lepidostomatidae (lepidostomatid caddisflies) Leptophlebiidae (pronggill mayflies) Leuctridae (rolled wing stoneflies) Naididae (naidid worms) Nematoda (nematodes) Nemouridae (nemourid stoneflies) Oligochaeta (aquatic earthworms) Perlodidae (perlodid stoneflies) Philopotamidae (fingernet caddisflies) Planariidae (flatworms) Planorbidae (planorbid snails) Plecoptera (unidentified stoneflies) Capniidae/Leuctridae (winter and spring stoneflies) Polycentropodidae (trumpetnet and tubemaking caddisflies) Psephenidae (water penny beetles) Psychomyiidae (nettube caddisflies) Pteronarcyidae (giant stoneflies) Pyralidae (aquatic pyralid moths) Rhyacophilidae (freeliving caddisflies) Sialidae (alderflies) Simuliidae (black flies) Tipulidae (crane flies) Uenoidae (stonecase caddisflies) Perlidae (common stoneflies) Ptilodactylidae (ptilodactylid beetles) Trichoptera (unidentified caddisflies)