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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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Goose
Posts: 77
Goose on Oct 17, 2006October 17th, 2006, 2:53 am EDT
Hi All! I have another caddis question. Are the colors of a caddis in its emerging pupa stage the same colors it will be as an adult when the transition is complete? I hope that makes sense.
Troutnut
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Bellevue, WA

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Troutnut on Oct 17, 2006October 17th, 2006, 4:35 am EDT
Yeah, they are. The "emerging pupa" is actually not a pupa, but something called a "pharate adult," which is a fully formed adult inside a pupal exoskeleton. That outer skin is transparent so you can pretty much see the final adult through it, minus the wings, which are still crunched up in the wingpads.
Jason Neuswanger, Ph.D.
Troutnut and salmonid ecologist
GONZO
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"Bear Swamp," PA

Posts: 1681
GONZO on Oct 17, 2006October 17th, 2006, 6:19 am EDT
Goose-

I would only add that adult caddisflies do darken after emergence. Mayflies do this as well; but, with mayflies, the lighter shade of the freshly emerged mayfly is what should be imitated during a hatch.
With caddisflies, the freshly emerged (lighter) adults are less important because most fly quickly after emerging. Imitations of adult caddisflies are most useful during egg-laying and will be darker.

You can see a good example of this darkening by comparing the freshly emerged adult to the "aged" adult on the Brachycentrus appalachia page.
Goose
Posts: 77
Goose on Oct 17, 2006October 17th, 2006, 6:43 am EDT
Thanks, Guys! The reason I asked is that since I know the adult color of the body, I can tie the pupas to match and be in the ballpark. Now, the larva is another entirely different color scheme, I suppose.
GONZO
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"Bear Swamp," PA

Posts: 1681
GONZO on Oct 17, 2006October 17th, 2006, 7:19 am EDT
Your "reverse engineering" approach should work, but I would make the pupal patterns a shade or two lighter.

Larval patterns are not applicable to caddisfly emergence or egg-laying, and are mostly "searching" patterns for non-hatch periods. Probably the most important of these are the free-living "Green Sedge" larvae of Rhyacophila spp. Jason has some good examples of these on the Rhyacophila page. Just remember that the larvae are larger than the pupae or adults.

A few Green Sedge larvae (also known as "Green Rockworms") and a few cased caddis patterns (or "Peeking Caddis") should be all you'll usually need in this regard.
Goose
Posts: 77
Goose on Oct 18, 2006October 18th, 2006, 1:04 am EDT
Gonzo: I fish a Rockworm pattern on the Juniata River most of the year and it does well. I dub it, rib, add a head and tie if off. Sometimes I get attacked by those that argue I'm fishing with a green weenie. There are green rockworms in the water and that's all I need to know! Ha! HA!
GONZO
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"Bear Swamp," PA

Posts: 1681
GONZO on Oct 18, 2006October 18th, 2006, 3:51 am EDT
Hi Goose-

I've always thought that some of the Green Weenie's infamous reputation was attributable to its ability to suggest Rhyacophila larvae. There are certainly better imitations of these larvae, but when it is fished along the bottom in the fast-water habitat that the "worms" favor, it serves as an adequate imitation even though many regard it as a mere "junk attractor."

I assume that when you say you fish the Juniata River you're referring to the "Little J." That river was the favorite of my dear departed friend, Norm Shires, and it is certainly the kind of water where getting to know the important hatches can pay big dividends. Keep working on your "bugology"--you'll be rewarded for your efforts.
Troutnut
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Troutnut on Oct 18, 2006October 18th, 2006, 4:49 am EDT
Gonzo, do you know which species correspond to the "September Peach Fly" and/or "October Sulphur" on the Little Juniata? I've been following a discussion about those on another forum and nobody seems to know which Latin names go with those popular bugs.
Jason Neuswanger, Ph.D.
Troutnut and salmonid ecologist
GONZO
Site Editor
"Bear Swamp," PA

Posts: 1681
GONZO on Oct 18, 2006October 18th, 2006, 6:42 am EDT
Jason-

I'm not familiar with the nicknames they are using, but I'd bet it's Leucrocuta hebe (Little Yellow Quill). I checked their descriptions, and everything seems to fit. On many streams in PA, it's an extremely underrated, little-known hatch.

Here's a description from my field notes that you might run by the guys on the other site: "dun abt. 6-7mm, creamy dun [gray] wing w/ darker markings around center [of costal margin] and dark crossveins throughout, creamy tan sternites w/ orange-brown tergites, two pale yellow tails and unmarked pale creamy yellow legs, tannish orange thorax, and large black eyes on male."

Up close, it looks like a little yellowish orange "Cahill" (miniature Maccaffertium). From a distance, it is easily mistaken for E. dorothea. Activity is usually concentrated around faster water, but can spill over into pools. It has a lengthy hatching period. On some streams, like the West Branch of the Delaware or the Little J, it can last into October.
Goose
Posts: 77
Goose on Oct 18, 2006October 18th, 2006, 7:05 am EDT
Thanks, Gonzo: If you're ever over this way give me a shout and we can fish the Little J.
GONZO
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"Bear Swamp," PA

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GONZO on Oct 18, 2006October 18th, 2006, 7:10 am EDT
Thanks, Goose. I'd enjoy that.
JAD
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Alexandria Pa

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JAD on Oct 20, 2006October 20th, 2006, 4:00 pm EDT
(Up close, it looks like a little yellowish orange "Cahill" (miniature Maccaffertium). From a distance, it is easily mistaken for E. dorothea. Activity is usually concentrated around faster water, but can spill over into pools. It has a lengthy hatching period. On some streams, like the West Branch of the Delaware or the Little J, it can last into October)
Quote
Hi guys Ill bet that's why I caught so many fish in the L-j
the end of September and early October.I used a 18 cream Coparadun and did quite well in the afternoon.

Caddisman1---Or JaD


They fasten red (crimson red) wool around a hook, and fix onto the wool two feathers which grow under a cock’s wattles, and which in colour are like wax.
Radcliffe's Fishing from the Earliest Times,
GONZO
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"Bear Swamp," PA

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GONZO on Oct 21, 2006October 21st, 2006, 4:41 am EDT
JAD/Caddisman 1-

Welcome to the "Little Yellow Quill Club!" It's an elite group comprised of bugheads, diehards, and accidental tourists. Unless you're in the "dry flies only" cult of the club, prepare a few little sulphur-colored wets for next season because Leucrocuta hebe often emerges a bit below the surface (not on the bottom like Quill Gordon, but within a foot of the top).

This hatch actually starts in late June or early July, but in hot weather the duns escape so quickly that neither trout nor anglers pay them much attention. As the weather cools and the other hatches disappear, L. hebe really comes into its own. The dry fly action is best on cool days, but the little wet can work anytime the LYQs are hatching.

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