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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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Lateral view of a Male Ephemera simulans (Ephemeridae) (Brown Drake) Mayfly Spinner from the Namekagon River in Wisconsin
Posts: 3
Jackson on May 26, 2009May 26th, 2009, 10:16 am EDT
Is the Coffin fly the male spinner of the Green Drake or does the Brown Drake also produce a white spinner?
Konchu's profile picture
Site Editor

Posts: 498
Konchu on May 26, 2009May 26th, 2009, 3:27 pm EDT
The Coffin Fly and Green Drake are different names for the same thing in the East. The Brown Drake is another species.
Posts: 3
Jackson on May 27, 2009May 27th, 2009, 2:55 am EDT
My understanding is that the Coffin Fly is the male spinner of the Green Drake and it is white when spent. Does the Eastern Brown Drake (different species) also have a white male spinner?? Can you have both species, Green and Brown, come off in the same waters (eastern spring creek) at the same time? The reason I ask is it appears that I have seen both on the water. Any really good way to distinguish these 2 species from each other besides the slight green color to the wings (green drake)?
Thanks, Ed
Wiflyfisher's profile picture

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Wiflyfisher on May 27, 2009May 27th, 2009, 5:06 am EDT
I can't say for out East, but I have never seen a Brown Drake spinner that looked like the Eastern Coffin Fly (Green Drake) in the Upper Midwest.
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"Bear Swamp," PA

Posts: 1681
GONZO on May 27, 2009May 27th, 2009, 6:01 am EDT
Does the Eastern Brown Drake...also have a white male spinner??
No, but it is only the abdomen of the Green Drake spinner that is whitish. The wings of the spinners retain the heavy blackish markings, and the thorax is dark. It is the funereal black-and-white coloration of the male spinners that led to the nickname, Coffin Flies. (The female spinners often have a yellowish tint to the abdomen due to underlying eggs.)

Can you have both species, Green and Brown, come off in the same waters...at the same time?
Yes, when they are present in the same waters, the emergence usually overlaps. However, March Browns (M. vicarium) are sometimes confused for Brown Drakes and vice versa. Look at the number of tails: March Browns will have two; Brown and Green Drakes will have three.

Any really good way to distinguish these two species from each other besides the slight green color to the wings (green drakes)?
Despite the name, not all populations of Green Drakes have a greenish tint. Green Drakes (E. guttulata) are typically larger than Brown Drakes (E. simulans). (Hatches gives the size range for Green Drakes as 18-30mm and Brown Drakes as 13-16mm, but I have seen female Brown Drakes up to 20mm.) Green Drake duns have creamy pale tan to dull yellowish abdomens with a darker brownish (sometimes dark olive) dorsal coloration. The wings are heavily marked with black or dark brown with a slightly yellowish (sometimes greenish) background. Brown Drake duns have tan or yellowish brown abdomens with dark brown patterning on the dorsal surface. The wings typically have dark brown markings on a grayish or yellowish tan background. Green Drakes lose the dark dorsal coloration upon transformation to spinners, but Brown Drakes retain the dark dorsal patterns in the spinner stage. (If you use the site search function to compare the photos of Ephemera guttulata to the photos of Ephemera simulans found on this site, the differences should become fairly obvious.)
Posts: 3
Jackson on May 27, 2009May 27th, 2009, 6:34 am EDT
Great info Gonzo! Thanks for the help. Jackson
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Palmyra PA

Posts: 3047
Martinlf on Jun 10, 2009June 10th, 2009, 3:23 pm EDT
I had very good luck with a pattern on the Delaware that uses a white foam post for the abdomen. It floats like a charm. Now to tie up some nuclear versions.
"He spread them a yard and a half. 'And every one that got away is this big.'"

--Fred Chappell

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