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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.

Case view of a Pycnopsyche guttifera (Limnephilidae) (Great Autumn Brown Sedge) Caddisfly Larva from the Yakima River in Washington
It's only barely visible in one of my pictures, but I confirmed under the microscope that this one has a prosternal horn and the antennae are mid-way between the eyes and front of the head capsule.

I'm calling this one Pycnopsyche, but it's a bit perplexing. It seems to key definitively to at least Couplet 8 of the Key to Genera of Limnephilidae Larvae. That narrows it down to three genera, and the case seems wrong for the other two. The case looks right for Pycnopsyche, and it fits one of the key characteristics: "Abdominal sternum II without chloride epithelium and abdominal segment IX with only single seta on each side of dorsal sclerite." However, the characteristic "metanotal sa1 sclerites not fused, although often contiguous" does not seem to fit well. Those sclerites sure look fused to me, although I can make out a thin groove in the touching halves in the anterior half under the microscope. Perhaps this is a regional variation.

The only species of Pycnopsyche documented in Washington state is Pycnopsyche guttifera, and the colors and markings around the head of this specimen seem to match very well a specimen of that species from Massachusetts on Bugguide. So I am placing it in that species for now.

Whatever species this is, I photographed another specimen of seemingly the same species from the same spot a couple months later.
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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Fenton, MI.

Posts: 28
Brian314 on Nov 11, 2018November 11th, 2018, 8:58 am EST
One of the early hatches in MI is the Slate Wing Mahogany. The dry fly versions of this are, confusingly, called Mahogany Dun and Blue Quill - Two completely different colors. (1) Does anyone know why ? (2) Does anyone know the fly patternrecipename for this fly in Mi - I want to tie it ?
Thanks !! Brian314
Roguerat's profile picture
Posts: 456
Roguerat on Nov 11, 2018November 11th, 2018, 11:27 pm EST

Welcome to another Michigander on the forum! You're up there in NW Kent Co, apparently...and a short trip to the Rogue or Muskegon.

Blue Quill refers to wing color (a dark grey/dun) and Little Mahogany (reddish, dark brown) refers to body coloration. Both are local names for Paraleptophebia spp. and a good earlier hatch for your local waters...Google these names and a bunch of patterns will turn up, and past experience shows sz 16 nymph and dry flies work best for me.

The Slate Wing Mahogany is another fly altogether- Isonychia spp. (sz's 10-12 with some smaller exceptions later in the season) which should appear in late June through August dependent on temps and other variables. This is a heavy and fairly dependable hatch on the Muskegon.

(asking forgiveness if you already know the above info, I'm often too willing to share stuff).

See you on the stream next spring...I'll be the whiskered old fart flogging the water with a trout spey-rod,

tight lines!


'Less is more...'

Ludwig Mies Vande Rohe

Roguerat's profile picture
Posts: 456
Roguerat on Nov 12, 2018November 12th, 2018, 5:37 am EST
My mistake in noting the Slate Wing Mahogany as an Iso, it IS another name for Paraleptophlebia spp.(thanks to the insect ID section of this forum and Dr Jason)

Isonychia spp. are known as a Slate Drakes or Mahogany Drakes, per Ann Miller's excellent 'Hatch Guide for Upper Midwest Streams', another valuable resource for tyers and fly-fishers alike.


"Less is more...'

Ludwig Mies Vande Rohe

Fenton, MI.

Posts: 28
Brian314 on Nov 23, 2018November 23rd, 2018, 9:23 pm EST
Thanks so much for taking the time clearing that up for me Roguerat !
RE Ann Miller's book - it is on my xmas list - if I don't get it at xmas, I'll just order it and give MYSELF a present...LOL !!!! Brian314

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