Photo of an alderfly larva among rocks and gravel in an aquarium.

    Alderfly Larvae

    Sialis spp.
    Photo of a spotted fishing spider perched on the water's surface amid floating duckweed plants

    Aquatic Spiders

    Dolomedes spp., Tetragnatha spp., and others
    brokenray

    Arkansas Brokenray

    Lampsilis reeveiana
    Photo of backswimmer, side view

    Backswimmers

    About 32 North American species in the family Notonectidae
    Gray, speckled, translucent gelatinous blob cut in half to show structure

    Bryozoans (Moss Animals)

    Freshwater species in the phylum Bryozoa
    butterfly

    Butterfly

    Ellipsaria lineolata
    Photo of caddisfly larva with case made of detritus

    Caddisfly Larvae

    Various species in the order Trichoptera
    Photo of crane fly larva

    Crane Fly Larvae

    There are over 500 species of crane flies in North America.
    deertoe

    Deertoe

    Truncilla truncata
    Photo of a devil crayfish.

    Devil Crayfish

    Lacunicambarus aff. diogenes
    ellipse

    Ellipse and Bleedingtooth

    Venustaconcha ellipsiformis and V. pleasii
    fatmucket

    Fatmucket

    Lampsilis siliquoidea
    Photo of a fishfly larva crawling among rocks in an aquarium.

    Fishfly Larvae

    Chauliodes, Neohermes, and Nigronia spp. (in eastern US)
    fragile papershell

    Fragile Papershell

    Leptodea fragilis
    Photo of a freckled crayfish.

    Freckled Crayfish

    Cambarus maculatus
    Monkey Face Mussel

    Freshwater Mussels

    Bivalve molluscs in order Unionoida
    Photo of several prosobranch pond snails crawling on a rock.

    Gilled Aquatic Snails (Prosobranch Pond Snails)

    Over 20 Missouri species in former subclass Prosobranchia
    Photo of a golden crayfish viewed through the surface of creek water.

    Golden Crayfish

    Faxonius luteus (formerly Orconectes luteus)
    Photo of a gray-speckled crayfish.

    Gray-Speckled Crayfish

    Faxonius palmeri (formerly Orconectes palmeri)
    Photo of a deer fly larva, probably in a petri dish, on a gray background.

    Horse and Deer Fly Larvae

    Tabanus, Chrysops, and related genera
    Photo of a horsehair worm in an aquarium

    Horsehair Worms

    About 350 species scientifically described.
    No photo available

    Hydras

    Various species in the genus Hydra
    Photo of a longpincered crayfish.

    Longpincered Crayfish

    Faxonius longidigitus (formerly Orconectes longidigitus)
    Photo of pulmonate snail crawling on rock

    Lunged Aquatic Snails (Pulmonate Pond Snails)

    Over 30 Missouri species in former subclass Pulmonata
    maple leaf

    Mapleleaf

    Quadrula quadrula
    Photo of a mayfly naiad crawling on rock underwater

    Mayfly Larvae

    There are hundreds of species in North America.
    mucket

    Mucket

    Actinonaias ligamentina
    pimpleback

    Pimpleback

    Quadrula pustulosa
    pink mucket

    Pink Mucket

    Lampsilis abrupta
    exclamation mark

    Endangered

    plain pocketbook

    Plain Pocketbook

    Lampsilis cardium
    Photo of a ramshorn snail on a wet rock.

    Ramshorn Snails

    Gyraulus, Helisoma, Menetus, Micromenetus, Planorbula spp.
    Photo of amphipod on a rock

    Scuds and Sideswimmers (Amphipods)

    Species in the crustacean order Amphipoda
    Photograph of Sheepnose freshwater mussel shell exterior view

    Sheepnose (Bullhead)

    Plethobasus cyphyus
    exclamation mark

    Endangered

    Snuffbox

    Snuffbox

    Epioblasma triquetra
    exclamation mark

    Endangered

    Photo of stonefly naiad on a rock underwater

    Stonefly Larvae

    There are hundreds of species in North America
    threeridge

    Threeridge

    Amblema plicata
    Photo of an aquatic tubificid worm among rocks in an aquarium.

    Tubificid Worms (Tubifex Worms)

    Tubifex spp. and other aquatic tubificid annelids
    Photo of a pink planarian on a rock.

    Turbellarians (Planarians; Free-Living Flatworms)

    Species in genera Dugesia, Planaria, etc.
    wartyback

    Wartyback

    Quadrula nodulata
    Photo of a collared water scavenger beetle showing back.

    Water Scavenger Beetles

    Beetles in the family Hydrophilidae
    yellow sandshell

    Yellow Sandshell

    Lampsilis teres