Artistic view of a Male Pteronarcys californica (Pteronarcyidae) (Giant Salmonfly) Stonefly Adult from the Gallatin River in Montana

Salmonflies
Pteronarcys californica

The giant Salmonflies of the Western mountains are legendary for their proclivity to elicit consistent dry-fly action and ferocious strikes.

Stream photos

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Neoleptophlebia Mayfly Nymph Neoleptophlebia Mayfly Nymph

Dorsal view of a Neoleptophlebia (Leptophlebiidae) Mayfly Nymph from the Yakima River in Washington

Some characteristics from the microscope images for the tentative species id: The postero-lateral projections are found only on segment 9, not segment 8. Based on the key in Jacobus et al. (2014), it appears to key to Neoleptophlebia adoptiva or Neoleptophlebia heteronea, same as this specimen with pretty different abdominal markings. However, distinguishing between those calls for comparing the lengths of the second and third segment of the labial palp, and this one (like the other one) only seems to have two segments. So I'm stuck on them both. It's likely that the fact that they're immature nymphs stymies identification in some important way.

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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.

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Male Stenonema terminatum Mayfly Spinner Pictures

I positively identified this specimen under a microscope with a good key. It was one of the more common species in a generally light mixed bag of mayflies over a big Catskill tailwater last night.

I swooped this one out of the air while it was mating with a female, so I can be certain about her ID as well.

Ruler view of a Male Stenonema terminatum (Heptageniidae) Mayfly Spinner from the West Branch of the Delaware River in New York The smallest ruler marks are 1 mm.

Lateral view of a Male Stenonema terminatum (Heptageniidae) Mayfly Spinner from the West Branch of the Delaware River in New York

Male Stenonema terminatum (Heptageniidae) Mayfly Spinner from the West Branch of the Delaware River in New York

Artistic view of a Male Stenonema terminatum (Heptageniidae) Mayfly Spinner from the West Branch of the Delaware River in New York

Dorsal view of a Male Stenonema terminatum (Heptageniidae) Mayfly Spinner from the West Branch of the Delaware River in New York

This mayfly was collected from the West Branch of the Delaware River in New York on June 7th, 2007 and added to Troutnut.com by Troutnut on June 8th, 2007.

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References

Jacobus, L. M., Wiersema, N.A., and Webb, J.M. 2014. Identification of Far Northern and Western North American Mayfly Larvae (Insecta: Ephemeroptera), North of Mexico; Version 2. Joint Aquatic Science meeting, Portland, OR. Unpublished workshop manual. 1-176.