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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.

Dorsal view of a Ephemerella mucronata (Ephemerellidae) Mayfly Nymph from the Yakima River in Washington
This is an interesting one. Following the keys in Merritt R.W., Cummins, K.W., and Berg, M.B. (2019) and Jacobus et al. (2014), it keys clearly to Ephemerella. Jacobus et al provide a key to species, but some of the characteristics are tricky to interpret without illustrations. If I didn't make any mistakes, this one keys to Ephemerella mucronata, which has not previously been reported any closer to here than Montana and Alberta. The main character seems to fit well: "Abdominal terga with prominent, paired, subparallel, spiculate ridges." Several illustrations or descriptions of this holarctic species from the US and Europe seem to match, including the body length, tarsal claws and denticles, labial palp, and gill shapes. These sources include including Richard Allen's original description of this species in North America under the now-defunct name E. moffatae in Allen RK (1977) and the figures in this description of the species in Italy.
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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Lateral view of a Male Calineuria californica (Perlidae) (Golden Stone) Stonefly Adult from the South Fork Snoqualmie River in Washington
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.
Millcreek
Healdsburg, CA

Posts: 344
Millcreek on Jul 22, 2019July 22nd, 2019, 9:18 am EDT
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
"If we knew what it was we were doing, it would not be called research, would it?"
-Albert Einstein
Troutnut
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Administrator
Bellevue, WA

Posts: 2758
Troutnut on Jul 22, 2019July 22nd, 2019, 11:24 am EDT
Thanks. The color patterns at least looks extremely similar to this Calineuria californica from bugguide.net:

https://bugguide.net/node/view/368894/bgimage

I tried following the key in Merritt & Cummins to get there, but none of the relevant characteristics were very clear unfortunately.

What's the size range for that one? One source said they're the largest western Perlid, and this specimen certainly doesn't fit that bill.
Jason Neuswanger, Ph.D.
Troutnut and salmonid ecologist
Millcreek
Healdsburg, CA

Posts: 344
Millcreek on Jul 22, 2019July 22nd, 2019, 12:26 pm EDT
The size range is from 15-25 mm from nose to tip of abdomen (not including the cerci). At least from this area of northern California.
"If we knew what it was we were doing, it would not be called research, would it?"
-Albert Einstein

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