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.

We were lucky to be able to fish through this storm as it skirted around us to the north, giving us just enough clouds to prompt a BWO hatch but keeping the lighting at a safe distance.

From Slough Creek in Wyoming

Stream photos

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Zapada cinctipes (Tiny Winter Black) Stonefly Nymph Zapada cinctipes (Tiny Winter Black) Stonefly Nymph

Dorsal view of a Zapada cinctipes (Nemouridae) (Tiny Winter Black) Stonefly Nymph from the Yakima River in Washington

Nymphs of this species were fairly common in late-winter kick net samples from the upper Yakima River. Although I could not find a key to species of Zapada nymphs, a revision of the Nemouridae family by Baumann (1975) includes the following helpful sentence: "2 cervical gills on each side of midline, 1 arising inside and 1 outside of lateral cervical sclerites, usually single and elongate, sometimes constricted but with 3 or 4 branches arising beyond gill base in Zapada cinctipes." This specimen clearly has the branches and is within the range of that species.

13 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.

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Male Calineuria californica (Golden Stone) Stonefly Adult Pictures

A few of these larger stoneflies were fluttering around the South Fork on an evening dominated by much smaller species.

This one has been difficult to identify. I can't spot any of the gill remnants characteristic of Perlidae, but the wing venation seems to point in that direction. I tried keying it out as Perlodidae but arrived at Isoperla, every western species of which has significantly smaller bodies than this one.

Edit: See forum comments for a likely correct identification.

Lateral view of a Male Calineuria californica (Perlidae) (Golden Stone) Stonefly Adult from the South Fork Snoqualmie River in Washington

Male Calineuria californica (Perlidae) (Golden Stone) Stonefly Adult from the South Fork Snoqualmie River in Washington

Ventral view of a Male Calineuria californica (Perlidae) (Golden Stone) Stonefly Adult from the South Fork Snoqualmie River in Washington

Ruler view of a Male Calineuria californica (Perlidae) (Golden Stone) Stonefly Adult from the South Fork Snoqualmie River in Washington The smallest ruler marks are 1 mm.

Taken with my usual glare-reducing polarized light and filter.

Male Calineuria californica (Perlidae) (Golden Stone) Stonefly Adult from the South Fork Snoqualmie River in Washington

Taken without my usual glare-reducing polarized light and filter, so the glare might enhance some details.

Male Calineuria californica (Perlidae) (Golden Stone) Stonefly Adult from the South Fork Snoqualmie River in Washington

I plan to try to start capturing wing venation in more of my photos for better identifiability.

Dorsal view of a Male Calineuria californica (Perlidae) (Golden Stone) Stonefly Adult from the South Fork Snoqualmie River in Washington

This stonefly was collected from the South Fork Snoqualmie River in Washington on July 20th, 2019 and added to Troutnut.com by Troutnut on July 22nd, 2019.

Discussions of this Adult

Hesperoperla or Calineuria

2 replies

Posted by Millcreek on Jul 22, 2019

Last reply on Jul 22, 2019 by Millcreek

Hesperoperla or Calineuria. Just a guess. These are similar to ones I've netted in California. The gill remnants don't always show and can be difficult to spot when they do. The size is right and the wing veining as well.

Here's a picture at bugguide of Hesperoperla.

https://bugguide.net/node/view/1257709

I'm leaning more towards Calineuria.
https://www.zoology.ubc.ca/~biodiv/entomology/main/Plecoptera/Perlidae/Calineuria%20californica%20(1dorsal).jpg

And here's a view of Hesperoperla's wings.

https:/bugguide.net/node/view/41324/bgimage

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References

Baumann, Richard W. 1975. Revision of the Stonefly Family Nemouridae (plecoptera) : a Study Of The World Fauna At The Generic Level. Smithsonian Contributions to Zoology undef(211): 1-74.