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

    Alderfly Larvae

    Sialis spp.
    Photo of an aquatic isopod in an aquarium, crawling on a rock.

    Aquatic Pillbugs and Sowbugs (Aquatic Isopods)

    Freshwater members of the crustacean order Isopoda
    Photo of a spotted fishing spider perched on the water's surface amid floating duckweed plants

    Aquatic Spiders

    Dolomedes spp., Tetragnatha spp., and others
    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.
    Photo of a spothanded crayfish viewed from above on white background.

    Crayfishes

    About 36 species in Missouri
    Photo of a damselfly nymph on rocks in an aquarium.

    Damselfly Larvae

    Species in the suborder Zygoptera
    deertoe

    Deertoe

    Truncilla truncata
    Photo of a devil crayfish.

    Devil Crayfish

    Lacunicambarus aff. diogenes
    Photo of a dragonfly larva resting on a stone.

    Dragonfly Larvae

    Species in the suborder Anisoptera
    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
    Monkey Face Mussel

    Freshwater Mussels

    Bivalve molluscs in order Unionoida
    giant floater

    Giant Floater

    Pygandon grandis
    Photo of a giant water bug

    Giant Water Bugs

    Species in the genera Abedus, Belostoma, and Lethocerus
    Venomous Icon

    Venomous

    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 hellgrammite

    Hellgrammite

    Corydalus cornutus
    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 leech

    Leeches

    Various species in the subclass Hirudinea
    lilliput

    Lilliput

    Toxolasma parvus
    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.
    Photo of a midge fly larva crawling on a rock in an aquarium

    Midge Fly Larvae

    Nearly 1,100 species in North America
    Photo of a gravid Mississippi grass shrimp in an aquarium.

    Mississippi Grass Shrimp

    Palaemonetes kadiakensis
    Photograph of several mosquito larvae resting at water surface

    Mosquito Larvae

    There are about 50 species of mosquitoes in our state.
    mucket

    Mucket

    Actinonaias ligamentina
    pimpleback

    Pimpleback

    Quadrula pustulosa
    pink papershell

    Pink Papershell

    Potamilus ohiensis
    plain pocketbook

    Plain Pocketbook

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

    Ramshorn Snails

    Gyraulus, Helisoma, Menetus, Micromenetus, Planorbula spp.
    round pigtoe

    Round Pigtoe

    Pleurobema sintoxia
    Photo of amphipod on a rock

    Scuds and Sideswimmers (Amphipods)

    Species in the crustacean order Amphipoda
    Photo of stonefly naiad on a rock underwater

    Stonefly Larvae

    There are hundreds of species in North America
    threehorn wartyback

    Threehorn Wartyback

    Obliquaria reflexa
    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.
    Photo of a northern, also called virile, crayfish.

    Virile Crayfish (Northern Crayfish)

    Faxonius virilis (formerly Oronectes virilis)
    wartyback

    Wartyback

    Quadrula nodulata
    Photo of a water boatman

    Water Boatmen

    About 125 species in North America in the family Corixidae
    Photo of a water nymph crayfish, side view of specimen carefully arranged against black background

    Water Nymph Crayfish

    Faxonius nais (formerly Orconectes nais)
    Photo of two water penny beetles clinging to a wet rock.

    Water Penny Beetle Larvae

    Beetles in the family Psephenidae

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