Stonefly Larva/Nymph

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Overview  Stonefly adult

Plecoptera

Mayfly larva  Caddisfly larva

Giant Stoneflies:
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1. "Giant Salmon Fly Nymph"
   Pteronarcys californica

2. "Golden Stonefly Nymph"
   Acroneuria californica

3. "Brown Willow Fly Nymph" Acroneuria pacifica

4. "Black Willow Fly Nymph"
   Acroneuria nigrita

5. "Orange Stonefly Nymph"
   Perla immarginata

6. "Great Stonefly Nymph"
   Perla capita

7. "Great Brown Stonefly Nymph"
   Acroneuria lycoris

8. "Giant Black Stonefly Nymph"
   Pteronarcys dorsata

Stonefly larva ("nymphs") are the only development stage between egg and adult; there are no pupa.  They are elongated and generally flattened to cylindrical in shape.  They average 5-35 mm in length (not including tails), but the largest are up to 60 mm.  The wing pads are usually visible.  They have 10 body segments.  Development takes 3 months to a year, but the largest species may take 2 to 3 years.  They are crawlers, rather than swimmers.  Adults emerge at all times of the year, but different species hatch at varying times.

Stoneflies are found in benthic habitats most often associated with flowing water and occasionally in cold lakes with lots of wave action.  They do not do well in polluted water.  Where coexisting with similar appearing mayflies, they can be distinguished from them by their lack of filamentous gills on the abdomen/body.

Stonefly larva typically climb out of the water to hatch.  This makes them more difficult to imitate with flies than either the mayflies or caddisflies, whose nymphs hatch in/from the water's surface.  Stonefly nymphs are usually best imitated by a mixture of upstream, dead-drift presentation, or casting down-&-across.

Smaller Stoneflies:
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1. "Yellow-Legged Stonefly"
   Acroneuria ruralis

2. "Little Green Stonefly"
   Alloperla imbecilla

3. "Early Black Stonefly"
   Capnia vernalis

4. "Little Olive Stonefly"
   Chloroperla coloradensis

5. "Little Yellow Stonefly"
   Isoperla bilineata

6. "Western Yellow Stonefly"
   Isoperla marmona

7. "Light Brown Stonefly"
   Isoperla signata

8. "Early Brown Stonefly"
   Taeniopteryx nivalis

9. "Little Red Stonefly"
   Taeniopteryx fasciata