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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 Grammotaulius betteni (Limnephilidae) (Northern Caddisfly) Caddisfly Larva from the Yakima River in Washington
This is a striking caddis larva with an interesting color pattern on the head. Here are some characteristics I was able to see under the microscope, but could not easily expose for a picture:
- The prosternal horn is present.
- The mandible is clearly toothed, not formed into a uniform scraper blade.
- The seems to be only 2 major setae on the ventral edge of the hind femur.
- Chloride epithelia seem to be absent from the dorsal side of any abdominal segments.
Based on these characteristics and the ones more easily visible from the pictures, this seems to be Grammotaulius. The key's description of the case is spot-on: "Case cylindrical, made of longitudinally arranged sedge or similar leaves," as is the description of the markings on the head, "Dorsum of head light brownish yellow with numerous discrete, small, dark spots." The spot pattern on the head is a very good match to figure 19.312 of Merritt R.W., Cummins, K.W., and Berg, M.B. (2019). The species ID is based on Grammotaulius betteni being the only species of this genus known in Washington state.
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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Douglasville, Ga

Posts: 3
Zugbuggin on Aug 20, 2010August 20th, 2010, 11:07 am EDT
Now that the temps are hi I've put up my fly rod and I'm spending time refilling my fly boxes getting ready for the Fall & Winter fishing. Last January & Febuary I spend time on the Chattogga River. At times saw spradic hatches of Early Black Stoneflys in sizes 16 & 18, there was very little surface activity so I went to the nymph. The closet thing I had was a Pheasant Tail #16 tied from dyed black pheasant tail with a copper rib which I did ok with. Does anybody have a pattern for a Early Black Stonefly nymph in a size #16 or #18
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"Bear Swamp," PA

Posts: 1681
GONZO on Aug 20, 2010August 20th, 2010, 11:51 am EDT
Just a thought, Tony: The little black stoneflies that you see in Jan. and Feb. are probably Capniidae. Despite the impression given by some tying books, the nymphs are usually more of a reddish brown or yellowish brown rather than black. A standard PT would make a pretty good imitation.

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