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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.
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.

By Troutnut on July 3rd, 2020
Looking to do something outdoors and asocial during July 4th of the year of Covid-19, I took my wife to a small stream full of feisty westslope cutthroat trout. Of course, being July 4th, there were a few people around the easy-to-access spots (i.e. places to drive and set up a cushy camp ten feet from the truck), but it was easy to walk past them and have a beautiful little stream to ourselves. I'm both baffled and grateful that so few people see the value in chasing little trout in pretty little streams.

Videos by Troutnut from Mystery Creek #249 in Washington

Cinygmula par mating flight

It's remarkable what thick hatches, and especially spinner flights, can come from a species few anglers have ever heard of. The genus Cinygmula is thought to produce unremarkable spinner flights, but this one would certainly have gotten the trout going if it weren't happening just before dark on a small stream where there isn't a lot of nocturnal feeding.

Photos by Troutnut from Mystery Creek #249 in Washington

Mystery Creek # 249 in Washington

Closeup insects by Troutnut from Mystery Creek #249 in Washington

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