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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.

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.
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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Drywaters has attached these 2 pictures to aid in identification. The message is below.
Cahills, slightly better pic of pump sample
Cahill spinners, October, 2006
Drywaters
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Selah, Wa.

Posts: 5
Drywaters on Nov 29, 2016November 29th, 2016, 10:53 am EST
Hi Roger, sorry to start a new thread on this topic, but couldn't figure out how to post more pics. Bruce.
Taxon
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Site Editor
Plano, TX

Posts: 1311
Taxon on Nov 29, 2016November 29th, 2016, 3:02 pm EST
Hi Bruce-


My guess would be that the imago in the lower right corner of your 2nd photo may be of genus Epeorus.
Best regards,
Roger Rohrbeck
www.FlyfishingEntomology.com
Millcreek
Healdsburg, CA

Posts: 344
Millcreek on Dec 3, 2016December 3rd, 2016, 5:53 am EST
Bruce-

I wonder if your nymph might be a Cinygmula or Cinygma species,see the links below.

For Cynigmula: http://www.troutnut.com/specimen/980

For Cynigma: http://www.troutnut.com/specimen/968
"If we knew what it was we were doing, it would not be called research, would it?"
-Albert Einstein
Drywaters
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Selah, Wa.

Posts: 5
Drywaters on Dec 3, 2016December 3rd, 2016, 9:39 am EST
Thanks Roger and Mark, will try to shoot better photos next year. What bits are important to include in the photos? The spring and fall Cahills appear to be the same mayfly, but perhaps not. Could the offspring from the spring Cahills mature in time to emerge in the fall? I'm pretty sure that the emergers and duns in the pump samples were the same bug, no other mayflies were emerging on that day.
Taxon
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Site Editor
Plano, TX

Posts: 1311
Taxon on Dec 3, 2016December 3rd, 2016, 3:03 pm EST
Could the offspring from the spring Cahills mature in time to emerge in the fall?


Bruce-

Not likely, as I the western Cahills are uni-voltine. However, there are different Cinygmula species emerging from early May through at least the end of September. One example of this would be Cinygmula ramaleyi, a mid-spring to early summer emerger, and Cinygmula reticulata, a mid-summer to early-fall emerger.
Best regards,
Roger Rohrbeck
www.FlyfishingEntomology.com
Millcreek
Healdsburg, CA

Posts: 344
Millcreek on Dec 4, 2016December 4th, 2016, 3:10 am EST
Bruce-

What bits are important to include in the photos?


If possible with the nymphs a complete ventral and dorsal photo, and a close up of the gills, also a close up of the head.

You might want to keep the nymph to send to someone who could take a look at it. Just plunk it in some alcohol.
"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 Dec 20, 2016December 20th, 2016, 1:13 pm EST
Hi Bruce,

I'm a bit late in replying to this one, but I would mainly just second what Roger said. It looks like Cinygmula or Cinygma. Species identification within these groups can be tricky. To tell the two genera apart, the most helpful shot would be a closeup dorsal view of a live, intact nymph, especially the head. Cinygmula has mouthparts that conspicuously stick out to the sides of the head when viewed from the top.
Jason Neuswanger, Ph.D.
Troutnut and salmonid ecologist

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