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Lateral view of a Male Baetis (Baetidae) (Blue-Winged Olive) Mayfly Dun from Mystery Creek #43 in New York

Blue-winged Olives
Baetis

Tiny Baetis mayflies are perhaps the most commonly encountered and imitated by anglers on all American trout streams due to their great abundance, widespread distribution, and trout-friendly emergence habits.

The Little Wood River in Idaho

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Clostoeca disjuncta (Northern Caddisfly) Caddisfly Larva Clostoeca disjuncta (Northern Caddisfly) Caddisfly Larva

Lateral view of a Clostoeca disjuncta (Limnephilidae) (Northern Caddisfly) Caddisfly Larva from the Yakima River in Washington

This one was surprisingly straightforward to identify. The lack of a sclerite at the base of the lateral hump narrows the field quite a bit, and the other options followed fairly obvious characteristics to Clostoeca, which only has one species, Clostoeca disjuncta.

11 Recently Added Photos

27" brown trout, my largest ever. It was the sub-dominant fish in its pool. After this, I hooked the bigger one, but I couldn't land it.

Troutnut is a project started in 2003 by salmonid ecologist Jason "Troutnut" Neuswanger to help anglers and fly tyers unabashedly embrace the entomological side of the sport. Learn more about Troutnut or support the project for an enhanced experience here.

Updates from January 12, 2004

Updates from January 12, 2004

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Videos by Troutnut from and the Marengo River in and Wisconsin

Dragonfly Nymph Scooting Around

Dragonfly nymphs propel themselves through the water with a miniature jet engine, taking water in below their mouths and shooting it out their back ends. You can see the ripples from the jet out this one's back in this video.

Featuring: Gomphidae Dragonfly Nymph

Shot on Jan 12, 2004

Added by Troutnut on Mar 30, 2006

Ephemera 1

Featuring: Ephemera simulans Mayfly Nymph

Shot on Jan 12, 2004

Added by Troutnut on Mar 30, 2006

Ephemera 2

This little Ephemera nymph swam around for a while and tried to burrow into the sand in my photography tank.

Featuring: Ephemera simulans Mayfly Nymph

Shot on Jan 12, 2004 from Marengo River in Wisconsin

Added by Troutnut on Mar 30, 2006

Closeup insects by Troutnut from the Namekagon River in Wisconsin

3
Ephemerella invaria (Sulphur) Mayfly Nymph

Ephemerella invaria (Ephemerellidae) (Sulphur) Mayfly Nymph from the Namekagon River in Wisconsin

3
Gasterosteidae (Stickleback) Fish Adult

Lateral view of a Gasterosteidae (Stickleback) Fish Adult from the Namekagon River in Wisconsin

Brook Stickleback Culea inconstans

3
Gasterosteidae (Stickleback) Fish Adult

Lateral view of a Gasterosteidae (Stickleback) Fish Adult from the Namekagon River in Wisconsin

Brook Stickleback Culea inconstans

4
Cottidae (Sculpin) Fish Adult

Lateral view of a Cottidae (Sculpin) Fish Adult from the Namekagon River in Wisconsin

Mottled Sculpin Cottus bairdi

1
Percidae (Perch, Walleyes, and Darters) Fish Adult

Lateral view of a Percidae (Perch, Walleyes, and Darters) Fish Adult from the Namekagon River in Wisconsin

Johnny Darter (Etheostoma nigrum)

3
Male Caecidotea (Cress Bug) Arthropod Adult

Dorsal view of a Male Caecidotea (Asellidae) (Cress Bug) Arthropod Adult from the Namekagon River in Wisconsin

4
Nigronia serricornis (Fishfly) Hellgrammite Larva

Dorsal view of a Nigronia serricornis (Corydalidae) (Fishfly) Hellgrammite Larva from the Namekagon River in Wisconsin

4
Belostoma flumineum (Electric Light Bug) Giant Water Bug Adult

Lateral view of a Belostoma flumineum (Belostomatidae) (Electric Light Bug) Giant Water Bug Adult from the Namekagon River in Wisconsin

I haven't seen the imitation of these things stressed, but in August 2003 on one of my favorite rivers the largest brown trout I kept had stomachs full of these things.

4
Cordulegaster Dragonfly Nymph

Dorsal view of a Cordulegaster (Cordulegastridae) Dragonfly Nymph from the Namekagon River in Wisconsin

This is a realy big, dark dragonfly nymph. Notice how "fuzzy" it is--it's covered with small hairs that collect sediment and debris and camouflage the nymph to match its natural surroundings. The greenish cast in some of the photos of this specimen is due to strange lighting during my first night photographing things for this site.

2
Gomphidae Dragonfly Nymph

Dorsal view of a Gomphidae Dragonfly Nymph from the Namekagon River in Wisconsin

3
Gomphidae Dragonfly Nymph

Dorsal view of a Gomphidae Dragonfly Nymph from the Namekagon River in Wisconsin

3
Tipulidae (Crane Fly) True Fly Larva

Tipulidae (Crane Fly) True Fly Larva from the Namekagon River in Wisconsin

2
Cambaridae Crayfish Juvenile

Dorsal view of a Cambaridae Crayfish Juvenile from the Namekagon River in Wisconsin

3
Capniidae (Snowfly) Stonefly Nymph

Dorsal view of a Capniidae (Snowfly) Stonefly Nymph from the Namekagon River in Wisconsin

3
Acroneuria lycorias (Golden Stone) Stonefly Nymph

Dorsal view of a Acroneuria lycorias (Perlidae) (Golden Stone) Stonefly Nymph from the Namekagon River in Wisconsin

2
Taeniopteryx (Early Black Stonefly) Stonefly Nymph

Dorsal view of a Taeniopteryx (Taeniopterygidae) (Early Black Stonefly) Stonefly Nymph from the Namekagon River in Wisconsin

7
Pteronarcys dorsata (Salmonfly) Stonefly Nymph

Dorsal view of a Pteronarcys dorsata (Pteronarcyidae) (Salmonfly) Stonefly Nymph from the Namekagon River in Wisconsin

4
Acroneuria lycorias (Golden Stone) Stonefly Nymph

Dorsal view of a Acroneuria lycorias (Perlidae) (Golden Stone) Stonefly Nymph from the Namekagon River in Wisconsin

The presence of anal gills, large dark spot in the center of the pale occipital bar point to lycorias.

3
Stenonema (March Browns and Cahills) Mayfly Nymph

Stenonema (Heptageniidae) (March Browns and Cahills) Mayfly Nymph from the Namekagon River in Wisconsin

3
Stenonema vicarium (March Brown) Mayfly Nymph

Stenonema vicarium (Heptageniidae) (March Brown) Mayfly Nymph from the Namekagon River in Wisconsin

3
Stenonema modestum (Cream Cahill) Mayfly Nymph

Stenonema modestum (Heptageniidae) (Cream Cahill) Mayfly Nymph from the Namekagon River in Wisconsin

7
Leptophlebia cupida (Black Quill) Mayfly Nymph

Leptophlebia cupida (Leptophlebiidae) (Black Quill) Mayfly Nymph from the Namekagon River in Wisconsin

5
Isonychia bicolor (Mahogany Dun) Mayfly Nymph

Isonychia bicolor (Isonychiidae) (Mahogany Dun) Mayfly Nymph from the Namekagon River in Wisconsin

5
Ephemerella invaria (Sulphur) Mayfly Nymph

Ephemerella invaria (Ephemerellidae) (Sulphur) Mayfly Nymph from the Namekagon River in Wisconsin

4
Ephemerella invaria (Sulphur) Mayfly Nymph

Ephemerella invaria (Ephemerellidae) (Sulphur) Mayfly Nymph from the Namekagon River in Wisconsin

2
Ephemerella invaria (Sulphur) Mayfly Nymph

Ephemerella invaria (Ephemerellidae) (Sulphur) Mayfly Nymph from the Namekagon River in Wisconsin

4
Ephemerella invaria (Sulphur) Mayfly Nymph

Ephemerella invaria (Ephemerellidae) (Sulphur) Mayfly Nymph from the Namekagon River in Wisconsin

3
Ephemerella (Hendricksons, Sulphurs, PMDs) Mayfly Nymph

Ephemerella (Ephemerellidae) (Hendricksons, Sulphurs, PMDs) Mayfly Nymph from the Namekagon River in Wisconsin

Morphologically this one looks a lot like subvaria but the color is really different.

4
Ephemerella subvaria (Hendrickson) Mayfly Nymph

Ephemerella subvaria (Ephemerellidae) (Hendrickson) Mayfly Nymph from the Namekagon River in Wisconsin

These are two common color patterns on Hendrickson nymphs. I suspect that one is male and the other female, but I don't know for sure.

1
Cottidae (Sculpin) Fish Adult

Lateral view of a Cottidae (Sculpin) Fish Adult from the Namekagon River in Wisconsin

Mottled Sculpin Cottus bairdi

2
Amphipoda (Scud) Arthropod Adult

Lateral view of a Amphipoda (Scud) Arthropod Adult from the Namekagon River in Wisconsin

2
Hydrophilidae (Giant Water Scavenger Beetle) Beetle Adult

Dorsal view of a Hydrophilidae (Giant Water Scavenger Beetle) Beetle Adult from the Namekagon River in Wisconsin

This is a water beetle. It is the hardest object in the world to pick up with tweezers. The second hardest is Mount Everest.

3
Stenonema (March Browns and Cahills) Mayfly Nymph

Stenonema (Heptageniidae) (March Browns and Cahills) Mayfly Nymph from the Namekagon River in Wisconsin

2
Stenonema (March Browns and Cahills) Mayfly Nymph

Stenonema (Heptageniidae) (March Browns and Cahills) Mayfly Nymph from the Namekagon River in Wisconsin

3
Stenonema (March Browns and Cahills) Mayfly Nymph

Stenonema (Heptageniidae) (March Browns and Cahills) Mayfly Nymph from the Namekagon River in Wisconsin

3
Stenonema (March Browns and Cahills) Mayfly Nymph

Stenonema (Heptageniidae) (March Browns and Cahills) Mayfly Nymph from the Namekagon River in Wisconsin

3
Isonychia (Slate Drake) Mayfly Nymph

Case view of a Isonychia (Isonychiidae) (Slate Drake) Mayfly Nymph from the Namekagon River in Wisconsin

This smaller Isonychia nymph was caught with a bunch of bicolor specimens, but it does not have the fluffy spine structure at the base of its gills. This might mean it's Isonychia sayi, or it might just be a bicolor nymph too young to have developed those structures.

4
Leucrocuta hebe (Little Yellow Quill) Mayfly Nymph

Leucrocuta hebe (Heptageniidae) (Little Yellow Quill) Mayfly Nymph from the Namekagon River in Wisconsin

This is a very early instar.

2
Leucrocuta hebe (Little Yellow Quill) Mayfly Nymph

Leucrocuta hebe (Heptageniidae) (Little Yellow Quill) Mayfly Nymph from the Namekagon River in Wisconsin

This is a very early instar.

2
Ephemerella invaria (Sulphur) Mayfly Nymph

Ephemerella invaria (Ephemerellidae) (Sulphur) Mayfly Nymph from the Namekagon River in Wisconsin

2
Ephemerella invaria (Sulphur) Mayfly Nymph

Ephemerella invaria (Ephemerellidae) (Sulphur) Mayfly Nymph from the Namekagon River in Wisconsin

2
Ephemerella invaria (Sulphur) Mayfly Nymph

Ephemerella invaria (Ephemerellidae) (Sulphur) Mayfly Nymph from the Namekagon River in Wisconsin

3
Ephemerella invaria (Sulphur) Mayfly Nymph

Ephemerella invaria (Ephemerellidae) (Sulphur) Mayfly Nymph from the Namekagon River in Wisconsin

2
Ephemerella invaria (Sulphur) Mayfly Nymph

Ephemerella invaria (Ephemerellidae) (Sulphur) Mayfly Nymph from the Namekagon River in Wisconsin

3
Ephemerellidae (Hendricksons, Sulphurs, PMDs, BWOs) Mayfly Nymph

Ephemerellidae (Hendricksons, Sulphurs, PMDs, BWOs) Mayfly Nymph from the Namekagon River in Wisconsin

3
Ephemerellidae (Hendricksons, Sulphurs, PMDs, BWOs) Mayfly Nymph

Ephemerellidae (Hendricksons, Sulphurs, PMDs, BWOs) Mayfly Nymph from the Namekagon River in Wisconsin

3
Ephemerella invaria (Sulphur) Mayfly Nymph

Ephemerella invaria (Ephemerellidae) (Sulphur) Mayfly Nymph from the Namekagon River in Wisconsin

3
Ephemerella invaria (Sulphur) Mayfly Nymph

Ephemerella invaria (Ephemerellidae) (Sulphur) Mayfly Nymph from the Namekagon River in Wisconsin

3
Ephemerella (Hendricksons, Sulphurs, PMDs) Mayfly Nymph

Ephemerella (Ephemerellidae) (Hendricksons, Sulphurs, PMDs) Mayfly Nymph from the Namekagon River in Wisconsin

3
Ephemerella invaria (Sulphur) Mayfly Nymph

Ephemerella invaria (Ephemerellidae) (Sulphur) Mayfly Nymph from the Namekagon River in Wisconsin

3
Ephemerella invaria (Sulphur) Mayfly Nymph

Ephemerella invaria (Ephemerellidae) (Sulphur) Mayfly Nymph from the Namekagon River in Wisconsin

2
Ephemerella invaria (Sulphur) Mayfly Nymph

Ephemerella invaria (Ephemerellidae) (Sulphur) Mayfly Nymph from the Namekagon River in Wisconsin

3
Ephemerella invaria (Sulphur) Mayfly Nymph

Ephemerella invaria (Ephemerellidae) (Sulphur) Mayfly Nymph from the Namekagon River in Wisconsin

3
Ephemerella invaria (Sulphur) Mayfly Nymph

Ephemerella invaria (Ephemerellidae) (Sulphur) Mayfly Nymph from the Namekagon River in Wisconsin

5
Ephemerellidae (Hendricksons, Sulphurs, PMDs, BWOs) Mayfly Nymph

Ephemerellidae (Hendricksons, Sulphurs, PMDs, BWOs) Mayfly Nymph from the Namekagon River in Wisconsin

4
Ephemerella subvaria (Hendrickson) Mayfly Nymph

Ephemerella subvaria (Ephemerellidae) (Hendrickson) Mayfly Nymph from the Namekagon River in Wisconsin

3
Epeorus vitreus (Sulphur) Mayfly Nymph

Epeorus vitreus (Heptageniidae) (Sulphur) Mayfly Nymph from the Namekagon River in Wisconsin

I suspect this is an Epeorus vitreus nymph. At the current instar, it's tough to make out the pair of dots on the tergites which signify that species, but with zooming and contrast enhancement they become evident.

3
Baetisca laurentina (Armored Mayfly) Mayfly Nymph

Baetisca laurentina (Baetiscidae) (Armored Mayfly) Mayfly Nymph from the Namekagon River in Wisconsin

4
Baetisca laurentina (Armored Mayfly) Mayfly Nymph

Baetisca laurentina (Baetiscidae) (Armored Mayfly) Mayfly Nymph from the Namekagon River in Wisconsin

3
Baetidae (Blue-Winged Olive) Mayfly Nymph

Baetidae (Blue-Winged Olive) Mayfly Nymph from the Namekagon River in Wisconsin

3
Baetidae (Blue-Winged Olive) Mayfly Nymph

Baetidae (Blue-Winged Olive) Mayfly Nymph from the Namekagon River in Wisconsin

2
Baetidae (Blue-Winged Olive) Mayfly Nymph

Baetidae (Blue-Winged Olive) Mayfly Nymph from the Namekagon River in Wisconsin

3
Baetidae (Blue-Winged Olive) Mayfly Nymph

Baetidae (Blue-Winged Olive) Mayfly Nymph from the Namekagon River in Wisconsin

This one's tails are chopped off and it's missing a leg.

4
Baetidae (Blue-Winged Olive) Mayfly Nymph

Baetidae (Blue-Winged Olive) Mayfly Nymph from the Namekagon River in Wisconsin

3
Baetidae (Blue-Winged Olive) Mayfly Nymph

Baetidae (Blue-Winged Olive) Mayfly Nymph from the Namekagon River in Wisconsin

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