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Lateral view of a Female Hexagenia limbata (Ephemeridae) (Hex) Mayfly Dun from the Namekagon River in Wisconsin
Hex Mayflies
Hexagenia limbata

The famous nocturnal Hex hatch of the Midwest (and a few other lucky locations) stirs to the surface mythically large brown trout that only touch streamers for the rest of the year.

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.
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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Millcreek has attached these 20 pictures to aid in identification. The message is below.
Fallceon quilleri nymph. Mature female. 7 mm (excluding cerci). Collected March 28, 2014. Dark variant.
Fallceon quilleri nymph. Immature male. 6 mm (excluding cerci). Collected October 29, 2014. Light variant.
Fallceon quilleri nymph. Mature female. 7 mm (excluding cerci). Collected March 28, 2014. Light variant.
Fallceon quilleri nymphs. Immature females. 6 mm (excluding cerci). Collected October 5, 2014.
Fallceon quilleri nymph. Mature male. 5.5 mm (excluding cerci). Collected November 11, 2013. Dark
variant.
Fallceon quilleri nymph. Mature female. 6.5 mm (excluding cerci). Collected November 1, 2014. Dark variant.
Fallceon thermophilos nymph. Mature male. 5.5 mm (excluding cerci). Collected July 15, 2014.
Fallceon thermophilos nymph. Mature male. 5.5 mm (excluding cerci). Collected October 7, 2014.
Fallceon thermophilos nymph. Mature female. 5.5 mm (excluding cerci). Collected April 21, 2014.
Fallceon thermophilos nymphs. Mature females. 5 - 5.5 mm (excluding cerci). Collected April 21, 2014.
Female Fallceon thermophilos and male Fallceon sp.1 nymph. Collected April 21, 2014.
Fallceon thermophilos nymphs. Mature male and female with female Fallceon quilleri nymph. Collected November 7, 2014.
Fallceon sp.1. Male nymph. 5 mm (excluding cerci). Collected October 15, 2014.
Fallceon sp.1. Male nymph. 5.5 mm (excluding cerci). Collected August 29, 2014.
Fallceon sp.1. and Fallceon thermophilos male nymphs. Collected August 29, 2014.
Fallceon sp.1. Male nymph. 5.5 mm (excluding cerci). Collected October 27, 2014.
Fallceon sp.1. Male nymph. 5 mm (excluding cerci). Collected August 29, 2014.
Fallceon sp.1. Male nymph. 5 mm (excluding cerci). Collected September 25, 2014.
Fallceon sp.1. and Fallceon quilleri male nymphs. Collected November 1, 2014.
Female Fallceon sp.1 nymph. 5 mm. Collected November 9, 2014.
Millcreek
Healdsburg, CA

Posts: 344
Millcreek on Nov 11, 2014November 11th, 2014, 12:59 pm EST
A while ago I did a post on what I thought were Baetis species nymphs. They turned out to be species of Fallceon. I got an email from Jeff Webb who thought one of the species might be Fallceon thermophilos based on some photos he had seen that Pat Randolph had taken. Got in touch with Pat and he sent a photo of a Fallceon thermophilos nymph and adult to me. The photo of the nymph matches the ones I had collected. Pat had collected the nymphs a few years earlier about half a mile downstream from where I got mine. Also found a partial description of the nymphs in an article by McCafferty, Meyer, Randolph and Webb "Evaluation of mayfly species originally described as Baetis Leach (Ephemeroptera: Baetidae) from California" (2008). The description of the larvae is on page 587. Link to article is http://www.ephemeroptera-galactica.com/pubs/pub_m/pubmccaffertyw2008p577.pdf

One of the other nymphs appears to be Fallceon quilleri. I found descriptions of the nymph in an article by Lugo-Ortiz, McCafferty and Waltz "Contribution to the taxonomy of the Panamerican genus Fallceon (Ephemeroptera: Baetidae)" (1994). http://www.ephemeroptera-galactica.com/pubs/pub_l/publugoc1994p460.pdf Morihara and McCafferty also give a description of the nymphs of Fallceon quilleri (as Baetis qulleri, a synonym) in "The Baetis larvae of North America (Ephemeroptera: Baetidae)" (1979). http://www.ephemeroptera-galactica.com/pubs/pub_m/pubmoriharad1979p139.pdf

As far as the third Fallceon nymph in the photos I have no idea what the species could be. Apparently there are unidentified species of Fallceon in California and this may be one of them. for now I'll just call it Fallceon sp.1.

I don't know how I misidentified the nymphs to Baetis in the first place (probably just butt stupid) but hopefully this ID is correct. I've removed the photos from the original post and placed them here along with some extra photos.
"If we knew what it was we were doing, it would not be called research, would it?"
-Albert Einstein
Konchu
Konchu's profile picture
Site Editor
Indiana

Posts: 498
Konchu on Nov 14, 2014November 14th, 2014, 12:52 pm EST
Really great photos. Thanks for sharing them.
Millcreek
Healdsburg, CA

Posts: 344
Millcreek on Nov 14, 2014November 14th, 2014, 4:32 pm EST
Luke -
Really great photos. Thanks for sharing them.

Thanks, you're welcome. As an aside, what is the mayfly nymph in the photo you have to the side of your posts?
"If we knew what it was we were doing, it would not be called research, would it?"
-Albert Einstein
Konchu
Konchu's profile picture
Site Editor
Indiana

Posts: 498
Konchu on Nov 21, 2014November 21st, 2014, 1:54 pm EST
It is a Teloganodes (Teloganodidae) species from Sri Lanka.
Millcreek
Healdsburg, CA

Posts: 344
Millcreek on Nov 21, 2014November 21st, 2014, 2:35 pm EST
Not Teloganodes jacobusi by any chance?:)
"If we knew what it was we were doing, it would not be called research, would it?"
-Albert Einstein

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