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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 Neoleptophlebia (Leptophlebiidae) Mayfly Nymph from the Yakima River in Washington
Some characteristics from the microscope images for the tentative species id: The postero-lateral projections are found only on segment 9, not segment 8. Based on the key in Jacobus et al. (2014), it appears to key to Neoleptophlebia adoptiva or Neoleptophlebia heteronea, same as this specimen with pretty different abdominal markings. However, distinguishing between those calls for comparing the lengths of the second and third segment of the labial palp, and this one (like the other one) only seems to have two segments. So I'm stuck on them both. It's likely that the fact that they're immature nymphs stymies identification in some important way.
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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Sandfly has attached these 2 pictures to aid in identification. The message is below.
Sandfly
tioga co. pa.

Posts: 33
Sandfly on Jan 15, 2015January 15th, 2015, 5:40 am EST
hatches in june,
sandfly
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N.J.B.B.A. #2215
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Martinlf
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Palmyra PA

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Martinlf on Jan 15, 2015January 15th, 2015, 5:49 am EST
Size?
"He spread them a yard and a half. 'And every one that got away is this big.'"

--Fred Chappell
Sandfly
tioga co. pa.

Posts: 33
Sandfly on Jan 15, 2015January 15th, 2015, 6:15 am EST
size 16 hook
sandfly
shop owner
N.J.B.B.A. #2215
Tiadaughton T.U. 688
I didn't Escape------They gave me a day pass !
Entoman
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Northern CA & ID

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Entoman on Jan 15, 2015January 15th, 2015, 10:20 am EST
The stout body and dramatic abdominal taper point to the genus Drunella. Telling the female adults apart taxonomically is way beyond my feeble skills but this specimen's size is on the small side for cornuta. My guess would be either cornutella or lata. From an angling perspective it's probably a distinction without a difference. Both are commonly called Small Blue-winged Olives.
"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
Crepuscular
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Boiling Springs, PA

Posts: 920
Crepuscular on Jan 15, 2015January 15th, 2015, 11:06 am EST
Pine Creek? Right after the drakes? Drunella tuberculata

see here: http://www.troutnut.com/topic/6711/2/Pine-Creek-Ephemerellid#31584
Timman
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white deer pike PA

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Timman on Jan 15, 2015January 15th, 2015, 11:33 am EST
I vote for lata. The abdomen in thinner than tuberculata like the sample posted.
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Crepuscular
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Boiling Springs, PA

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Crepuscular on Jan 15, 2015January 15th, 2015, 12:53 pm EST
I vote for lata. The abdomen in thinner than tuberculata like the sample posted.


What if she already laid her eggs?
Timman
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white deer pike PA

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Timman on Jan 15, 2015January 15th, 2015, 1:09 pm EST
To the best of my knowledge the only time the abdomen shrinks is when the adults reach the dehydration stage within hours of termination. I could be a Drunella tuberculata I just think lata is more likely.
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Crepuscular
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Boiling Springs, PA

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Crepuscular on Jan 15, 2015January 15th, 2015, 2:53 pm EST
To the best of my knowledge the only time the abdomen shrinks is when the adults reach the dehydration stage within hours of termination. I could be a Drunella tuberculata I just think lata is more likely.


Oh yeah it could be D.lata but I think the abdomen has to contract a little after oviposition.And the way the female in the photo is holding her abdomen like there used to be a ball of eggs there tells me she has already deposited her eggs. Based on my experience with Pine Creek in June, D. tuburculata is a very significant emergence. I hope sandfly responds with where it was collected. So I suppose like Kurt pointed out once again faced with a female of a genus that is not easy under good circumstances to separate out the species. At least we are close on genus. ;)
PaulRoberts
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Colorado

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PaulRoberts on Jan 15, 2015January 15th, 2015, 5:12 pm EST
Pure awesomeness.
Timman
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white deer pike PA

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Timman on Jan 15, 2015January 15th, 2015, 5:16 pm EST
Contraction and shrinkage are two different actions. The 8th - 10th look ever thin on the sample and thicker on the tuberculata specimen. That viewpoint is based on and is more visible in photo #2

She may have egged out, it is tough to say but it looks like both tuberculata & lata are very plausible.
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Entoman
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Northern CA & ID

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Entoman on Jan 15, 2015January 15th, 2015, 5:29 pm EST
Ah, I think you're probably right, Eric. Local info is always the best. I shouldn't have limited it to those two by implication. Walkeri was another viable option I neglected to mention as well. I see nothing in the photos that helps taxonomically to rule any of them out. Heck, I can't even eliminate cornuta with absolute certainty - though I think I'm probably safe based on size and time of year with that one.

The curved abdominal posture is common with all ephemerellid females. A foreshortening and loss of mass occurs during ovipositing and that has certainly occurred here. However, I'm not sure of the relevance as any differences in general abdominal conformation between these species have not been documented as having any diagnostic value to my knowledge.
"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
Timman
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white deer pike PA

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Timman on Jan 15, 2015January 15th, 2015, 7:34 pm EST
This is a good conversation; I haven’t seen either species in person in years, however;

When a larva molts to the adult stage only the digestive track is discarded to make why for reproductive organs, which commonly takes place in the last instars of the larva stage. Inside the exoskeleton all of the respiratory, vascular systems, and muscular structure remain intact. And, the spiracles replace the gills in the adult stages. Even at the point of dehydration the shell dimensions of the abdomen remain the same. At the point of expiration the abdomen laterally flattens out and collapses in the male, and becomes indentures on the ventral side in the females. The shell circumference from spiracle fold to spiracle fold, remains the same size as it was before dehydration or ovipositing in the female.

In other words if I measure the males abdomen per-death and it is 1.75mm high. After dehydration that number is the same only the lateral measurement has changed not the height. In the female it is opposite the height changes because of the concave compression in sternites 1-7 to the ventral side caused from dehydration with or without eggs present in the cavity.

Foreshortening is the better word for the contraction process that takes place after ovipositing. So if the sample is alive and in overall health only the length should change slightly.


In a great conversation it’s not the right or wrong it all about the content :-)


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Sandfly
tioga co. pa.

Posts: 33
Sandfly on Jan 19, 2015January 19th, 2015, 6:40 am EST
She had laid the eggs against the house right before this pic was taken
sandfly
shop owner
N.J.B.B.A. #2215
Tiadaughton T.U. 688
I didn't Escape------They gave me a day pass !
MiltRPowell
Posts: 106
MiltRPowell on Jan 25, 2015January 25th, 2015
Sandfly, really enjoyed the post, nice photos,great reads on guys thoughts, veiws. I read it threw twice. I'll just wonder what you named the babies.L.O.L.-M.R.P.

flyfishingthecreekM.R.P.

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