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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 Pycnopsyche guttifera (Limnephilidae) (Great Autumn Brown Sedge) Caddisfly Larva from the Yakima River in Washington
This specimen appears to be of the same species as this one collected in the same spot two months earlier. The identification of both is tentative. This one suffered some physical damage before being photographed, too, so the colors aren't totally natural. I was mostly photographing it to test out some new camera setting idea, which worked really well for a couple of closeups.
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.
Troutnut is a project started in 2003 by salmonid ecologist Jason "Troutnut" Neuswanger to help anglers and fly tyers unabashedly embrace the entomological side of the sport. Learn more about Troutnut or support the project for an enhanced experience here.

Lateral view of a Male Afghanurus inconspicua (Heptageniidae) Mayfly Dun from the East Branch of the Delaware River in New York
This pretty little dun was part of a sparse midsummer evening hatch on a large Catskill river.

I could not identify it by following a species key step by step, but I tentatively keyed it to the genus Nixe, and based on distribution maps and physical descriptions the most likely species is Nixe inconspicua. (Edit in 2023: this species was recently moved from Nixe into Afghanurus.)
Troutnut
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Troutnut on Jul 5, 2006July 5th, 2006, 1:24 pm EDT
I'll have to revisit the identification on this one. Originally the fore tarsal ratio made me think it's not Epeorus, but the unmarked wings, costal wing venation, and contiguous eyes now make me think otherwise.
Jason Neuswanger, Ph.D.
Troutnut and salmonid ecologist
Entoman
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Northern CA & ID

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Entoman on Sep 15, 2011September 15th, 2011, 2:28 am EDT
Hi Jason,

This probably isn't Nixe. Besides The eyes and weak basal crossveins of the forewings, the mesonotum lacks a transverse suture which also indicates Epeorus. I can see why the legs caused confusion. The foretarsi basal segment to 2nd segment length ratios in Merritt are a little confusing. The femora markings are very weak but look like they may be there.

Mack -

FWIW, I think you may be right about the genus but I don't think it's E. vitreus. My guess based on the terga patterns and tails is that it is a more obscure species. Sorting them out is problematic at best.

2 tails locks that down more than everything else.

I think you are confusing heptageniid adult stages with the nymphs. If this were a nymph you would be correct in your supposition, but all adult heptageniids have only two tails.

Regards,

Kurt
"It's not that I find fishing so important, it's just that I find all other endeavors of Man equally unimportant... And not nearly as much fun!" Robert Traver, Anatomy of a Fisherman
GONZO
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GONZO on Sep 15, 2011September 15th, 2011, 10:21 am EDT
This probably isn't Nixe. Besides The eyes and weak basal crossveins of the forewings, the mesonotum lacks a transverse suture which also indicates Epeorus.

Sorry to disagree, guys, but I believe that Jason's genus-level ID (Nixe) is correct. I doubt that this is N. inconspicua, which usually has uniformly colored dorsal abdominal segments.

Male Nixe have eyes that are contiguous (or nearly so), and the members of this genus also have weak basal costal crossveins in the forewings. (See Flowers 1980.) The mesonotum does have a transverse suture, and its shape is typical of this genus. The 1st tarsal segment is significantly shorter and not "subequal" (nearly equal) to the 2nd segment. The long 3rd and 4th segments of the claspers are consistent with this genus (2nd segment longer than 3rd and 4th segments combined in Epeorus). The dorsal abdominal markings (pale areas comprised of longitudinal whitish medial and adjacent “submesal” marks) and the overall appearance are typical of several Nixe species.

To get very technical, the medial depression of the mesothoracic furcasternum in this specimen is parallel-sided, which places this specimen clearly in the Ecdyonurinae (the subfamily of Nixe). That depression is convergent anteriorly in Epeorus and other members of the Rhithrogeninae (and in members of the Heptageniinae). (See Webb and McCafferty 2008.)
Entoman
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Entoman on Sep 15, 2011September 15th, 2011, 12:31 pm EDT
Sorry to disagree, guys


On the contrary Lloyd, I'm glad you took the time to do so.

The mesonotum does have a transverse suture, and its shape is typical of this genus.


Wow, this is really the crux of the matter. I'm seeing what appears to be a lateroparapsidal suture but not a transverse suture. I agree the medial depression in the mesothoracic furcasternum in this specimen looks to be parallel-sided, but don't we have to get past the mesonotal transverse suture to get to that?

I also agree that the eyes, wings and tarsi aren't the big issues between the genera as both can share similar traits. Merritt does mention tarsi segment ratios of one fifth to one half, but it is well below Epeorus determination in the couplets so cannot necessarily be concluded to exclude Epeorus as it would if it occurred above. This is my understanding anyway, but I can't deny it causes me concern.:)

Thanks,

Kurt
"It's not that I find fishing so important, it's just that I find all other endeavors of Man equally unimportant... And not nearly as much fun!" Robert Traver, Anatomy of a Fisherman
Entoman
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Entoman on Sep 16, 2011September 16th, 2011, 2:00 am EDT
Jason & Mack,

After looking at it more closely, Gonzo's points are well made and I believe he is right. The furcasternum characteristics he points out are pretty conclusive evidence against Epeorus and the transverse suture (though very subtle and hard to make out) is there, it's just very close to the anterior break in the mesonotum.

Regards,

Kurt
"It's not that I find fishing so important, it's just that I find all other endeavors of Man equally unimportant... And not nearly as much fun!" Robert Traver, Anatomy of a Fisherman
GONZO
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GONZO on Sep 16, 2011September 16th, 2011, 12:04 pm EDT
OK, before Bruce chastizes me for the "medial depression of the mesothoracic furcasternum" nonsense....The only analogy that comes to mind is probably somewhat inappropriate, but here goes:

Although this is a "guy" mayfly, it's a bit like evaluating women by the shape of their cleavage. In other words, if you were a mayfly (educated at Purdue), and your wife was a mayfly, and she caught you staring at the chest of another mayfly, you could say, "Honey, I was just admiring the shape of the medial depression of her mesothoracic furcasternum." (And then she would probably deny you access to her subgenital plate for the duration of the mating swarm.)
Oldredbarn
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Novi, MI

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Oldredbarn on Sep 16, 2011September 16th, 2011, 12:41 pm EDT
OMG! G...I love it! I'm tearing up here...I kid you not. This is funnier than the story I read once where Einstein and his pals at some conference were trying to calculate the physics involved with a gravity-defying strapless dress. :)

Or light passing through one of their beer bottles...I can't remember which.

This is a gem and if I have a vote, it gets moved to the best quote thread...At the top of the list! Especially for getting the drop on Bruce...:)

Spence
"Even when my best efforts fail it's a satisfying challenge, and that, after all, is the essence of fly fishing." -Chauncy Lively

"Envy not the man who lives beside the river, but the man the river flows through." Joseph T Heywood
Taxon
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Taxon on Sep 16, 2011September 16th, 2011, 12:46 pm EDT
Lloyd-

Not sure about Bruce, but if you get that analogy past Louis, you will probably be okay. :-)
Best regards,
Roger Rohrbeck
www.FlyfishingEntomology.com
GONZO
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"Bear Swamp," PA

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GONZO on Sep 16, 2011September 16th, 2011, 3:07 pm EDT
Yeah, our pal Louis is a bit sensitive about sexual innuendo when it concerns insects. I think he was a bug in a previous life, and he misbehaved and had to come back as an English professor. :)
Oldredbarn
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Oldredbarn on Sep 17, 2011September 17th, 2011, 12:49 pm EDT
I have to tell this story...

My wife and her staff had a rather rough way to go yesterday at work. Afterwards I remembered we had won a $100 gift credit card somewhere back down the road and I told her to drag it out of the drawer and we were going out to eat. This is a big gesture boys since according to her I'm a Hobbitt whenever I'm not in Grayling.

We made it to the restaurant and had a wonderful evening. On our way there I tried to explain the course of this thread and where Gonzo, more out of frustration than anything else, took it off-color. I forgot to take the printout of it that I had made before leaving the office in to the restaurant as well as my glasses.

My wife has a cut off limit in terms of how long she can listen to her husband go on about trees, birds, and anything related to our fair sport. I have the same problem when she brings up color swatches...

Anyway...I wasn't sure she was really paying attention when I was telling her about G's post and inuendo (sp?). So,imagine my surprise when this morning I came down to breakfast knowing she had a very long day planned for us of trips to home improvement stores and women's shoe sales etc...and the following took place...She was more than a little proud of herself:

I was standing in the kitchen when she came up to me with this smirk on her face. She was wearing her robe and she placed both of my hands in hers and then along each side of her breasts and exagerating her cleavage with my hands proclaimed, "Dear. This is the medial depression of my mesothoratic furcasternum!"

I just don't know what to say! She did make mention that the sports bar we ended up in last night had more than its share of females showing theirs off for all to see...I think it's the "look" these days. Not that Spence was paying any attention.

Ummm...Thanks G! ;)

Spence
"Even when my best efforts fail it's a satisfying challenge, and that, after all, is the essence of fly fishing." -Chauncy Lively

"Envy not the man who lives beside the river, but the man the river flows through." Joseph T Heywood
GONZO
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GONZO on Sep 17, 2011September 17th, 2011, 1:05 pm EDT
No...thank you, Spence! And thank your wife for me. She just made my day. (Vicariously, of course.) :)
Oldredbarn
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Posts: 2600
Oldredbarn on Sep 17, 2011September 17th, 2011, 1:29 pm EDT
Oops! I thought this was a PM!

Spence
"Even when my best efforts fail it's a satisfying challenge, and that, after all, is the essence of fly fishing." -Chauncy Lively

"Envy not the man who lives beside the river, but the man the river flows through." Joseph T Heywood
Entoman
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Northern CA & ID

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Entoman on Sep 22, 2011September 22nd, 2011, 3:36 am EDT
Which do you find the most interesting to look at - the medial depressions of the mesothoracic furcasternum that are parallel sided or the ones that diverge posteriorly? Personally, I don't care much for the latter...
"It's not that I find fishing so important, it's just that I find all other endeavors of Man equally unimportant... And not nearly as much fun!" Robert Traver, Anatomy of a Fisherman
Oldredbarn
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Novi, MI

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Oldredbarn on Sep 22, 2011September 22nd, 2011, 6:50 am EDT
Kurt,

We was wondering when you might show back up here...:)

Spence

"Even when my best efforts fail it's a satisfying challenge, and that, after all, is the essence of fly fishing." -Chauncy Lively

"Envy not the man who lives beside the river, but the man the river flows through." Joseph T Heywood
Entoman
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Northern CA & ID

Posts: 2604
Entoman on Sep 22, 2011September 22nd, 2011, 9:54 am EDT
Yeah, got lost in the woods for 5 days. The fishing was great, though.
"It's not that I find fishing so important, it's just that I find all other endeavors of Man equally unimportant... And not nearly as much fun!" Robert Traver, Anatomy of a Fisherman
Oldredbarn
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Novi, MI

Posts: 2600
Oldredbarn on Sep 22, 2011September 22nd, 2011, 12:20 pm EDT
The fishing was great, though.


You teaser! ;)

Spence
"Even when my best efforts fail it's a satisfying challenge, and that, after all, is the essence of fly fishing." -Chauncy Lively

"Envy not the man who lives beside the river, but the man the river flows through." Joseph T Heywood

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