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Lateral view of a Male Baetis (Baetidae) (Blue-Winged Olive) Mayfly Dun from Mystery Creek #43 in New York
Blue-winged Olives

Tiny Baetis mayflies are perhaps the most commonly encountered and imitated by anglers on all American trout streams due to their great abundance, widespread distribution, and trout-friendly emergence habits.

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.

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Wbranch's profile picture
York & Starlight PA

Posts: 2635
Wbranch on Jan 8, 2013January 8th, 2013, 8:02 am EST
Great pictures! The ones of the bridge are behind Harry Darbee's house. I've fished there many times. The fish always hang on the left side as there is deeper water there. Down stream by the old abutment used to be tons of stocked browns.

I couple of the other pictures look like they were taken at what we used to call "The Power Enclosure". About three miles upstream from the bridge pictures and just below the beginning of the No-Kill water. Am I right? I've caught some of the few rainbows I've ever caught on the Willow in that riffle.
Catskill fly fisher for fifty-five years.
Troutnut's profile picture
Bellevue, WA

Posts: 2758
Troutnut on Jan 8, 2013January 8th, 2013, 8:40 am EST
Some of them are from what I've heard called "Power-Line Pool," which I'd guess is the same thing.
Jason Neuswanger, Ph.D.
Troutnut and salmonid ecologist
Wbranch's profile picture
York & Starlight PA

Posts: 2635
Wbranch on Jan 8, 2013January 8th, 2013, 9:27 am EST

"Some of them are from what I've heard called "Power-Line Pool," which I'd guess is the same thing."

Yes, that's it! I used to park my 1969 VW Campmobile either at the upper end or down near the flat water pool and stay there all weekend. I'll look at some of my scanned prints to see if I have any from the "olden days" of my youth.
Catskill fly fisher for fifty-five years.
Entoman's profile picture
Northern CA & ID

Posts: 2604
Entoman on Jan 9, 2013January 9th, 2013, 4:42 pm EST
Interesting behavior by those caddis. Don't think it's mating. Could they be obtaining something from that lichen or whatever the growth is?
"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
Taxon's profile picture
Site Editor
Plano, TX

Posts: 1311
Taxon on Jan 9, 2013January 9th, 2013, 10:59 pm EST
Hi Jason-

I'm not sure what the caddisflies in this tight cluster are doing, but I'd guess it has something to do with mating. They scooted all around the rock, with some flies leaving the cluster and new ones coming all the time.

Unless I'm mistaken, the scientific term for this is cluster****.

Sorry Lewis, but I simply couldn't resist Jason's cleverly baited hook. :-)
Best regards,
Roger Rohrbeck

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