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 North Fork Couer d'Alene River in Idaho

Stream photos

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Female Sweltsa borealis (Boreal Sallfly) Stonefly Adult Female Sweltsa borealis (Boreal Sallfly) Stonefly Adult

Lateral view of a Female Sweltsa borealis (Chloroperlidae) (Boreal Sallfly) Stonefly Adult from Harris Creek in Washington

I was not fishing, but happened to be at an unrelated social event on a hill above this tiny creek (which I never even saw) when this stonefly flew by me. I assume it came from there. Some key characteristics are tricky to follow, but process of elimination ultimately led me to Sweltsa borealis. It is reassuringly similar to this specimen posted by Bob Newell years ago. It is also so strikingly similar to this nymph from the same river system that I'm comfortable identifying that nymph from this adult. I was especially pleased with the closeup photo of four mites parasitizing this one.

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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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Heptagenia pulla (Golden Dun) Mayfly Nymph Pictures

I used a microscope to positively identify this nymph as Heptagenia pulla. (Edit six years later: I wish I had explained why I was positive about this. It may have been based on color patterns in an angling text, which are not especially reliable for species ID anymore.)

Lateral view of a Heptagenia pulla (Heptageniidae) (Golden Dun) Mayfly Nymph from the Long Lake Branch of the White River in Wisconsin

Ventral view of a Heptagenia pulla (Heptageniidae) (Golden Dun) Mayfly Nymph from the Long Lake Branch of the White River in Wisconsin

Heptagenia pulla (Heptageniidae) (Golden Dun) Mayfly Nymph from the Long Lake Branch of the White River in Wisconsin

This mayfly was collected from the Long Lake Branch of the White River in Wisconsin on June 5th, 2005 and added to Troutnut.com by Troutnut on May 25th, 2006.

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