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

Blue-winged Olives
Baetis

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.

Waterfalls over smooth bedrock above Titcomb Lakes

From Titcomb Basin in Wyoming

Stream photos

Featured on the forum

Re: Trico emergers
In the Mayfly Genus Tricorythodes by Bwoklink (Martinlf replied)

Re: Trico Tips
In the Mayfly Genus Tricorythodes by Martinlf

Re: UV spectrum and trout
In General Discussion by Martinlf

Re: closing the gender gap in flyfishing
In General Discussion by Konchu (Smallflyguy replied)

Re: Fishing Kupa River, Slovenia
In Fishing Reports by Slocum (Fish1 replied)

Ephemerella mucronata Mayfly Nymph Ephemerella mucronata Mayfly Nymph

Dorsal view of a Ephemerella mucronata (Ephemerellidae) Mayfly Nymph from the Yakima River in Washington

This is an interesting one. Following the keys in Merritt R.W., Cummins, K.W., and Berg, M.B. (2019) and Jacobus et al. (2014), it keys clearly to Ephemerella. Jacobus et al provide a key to species, but some of the characteristics are tricky to interpret without illustrations. If I didn't make any mistakes, this one keys to Ephemerella mucronata, which has not previously been reported any closer to here than Montana and Alberta. The main character seems to fit well: "Abdominal terga with prominent, paired, subparallel, spiculate ridges." Several illustrations or descriptions of this holarctic species from the US and Europe seem to match, including the body length, tarsal claws and denticles, labial palp, and gill shapes. These sources include including Richard Allen's original description of this species in North America under the now-defunct name E. moffatae in Allen RK (1977) and the figures in this description of the species in Italy.

17 Recently Added Photos

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.

Female Leptophlebia (Black Quill) Mayfly Dun Pictures

I collected this mayfly after user Al514 tipped me off to the presence of some Leptophlebia mayflies I didn't seem to have yet with his ID request of a male dun. This seems to be of the same species. I also collected a female spinner. Based on that spinner, I can tell that this is either Leptophlebia cupida or Leptophlebia nebulosa, but I can't tell which.

Unfortunately none of the specimens I collected made it through the hot, sunny day very well. So the pictures aren't great, but they're better than nothing.

Ventral view of a Female Leptophlebia (Leptophlebiidae) (Black Quill) Mayfly Dun from Factory Brook in New York

Lateral view of a Female Leptophlebia (Leptophlebiidae) (Black Quill) Mayfly Dun from Factory Brook in New York

Female Leptophlebia (Leptophlebiidae) (Black Quill) Mayfly Dun from Factory Brook in New York

Dorsal view of a Female Leptophlebia (Leptophlebiidae) (Black Quill) Mayfly Dun from Factory Brook in New York

This specimen is on the left in this picture. On the right is another one I collected but didn't otherwise photograph. It's from the same stream and time, and presumably of the same species. It shows quite a bit of natural variation.

Ruler view of a Female Leptophlebia (Leptophlebiidae) (Black Quill) Mayfly Dun from Factory Brook in New York The smallest ruler marks are 1 mm.

This specimen (left) pictured next to a smaller one of apparently the same species (right).

Female Leptophlebia (Leptophlebiidae) (Black Quill) Mayfly Dun from Factory Brook in New York

This mayfly was collected from Factory Brook in New York on May 9th, 2007 and added to Troutnut.com by Troutnut on May 18th, 2007.

Discussions of this Dun

Borcher's Drake

3 replies

Posted by Oldredbarn on May 10, 2010

Last reply on May 13, 2010 by TNEAL

I will apologise up front here for railing on about another "Michigan" thing, but here goes...There is a rather famous fly from the Au Sable area originally put together by Ernie Borchers called the Borchers Drake and it was designed to cover this bug. Originally the abdomen was wrapped condor quill but wrapped natural turkey tail fibers are used now. The tail is three moose mane fibers tied longer than normal and on these specimens of Jason's you can see why that works. It's tied in a Catskill style or as a parachute pattern. Hackle is Adams style and the wing is light blue dun...Have at it!

Spence

Start a Discussion of Dun

References

Allen RK. 1977. New species of Ephemerella (Ephemerella) from Alberta (Ephemeroptera: Ephemerellidae). The Pan-Pacific Entomologist 53: 286-286.
Jacobus, L. M., Wiersema, N.A., and Webb, J.M. 2014. Identification of Far Northern and Western North American Mayfly Larvae (Insecta: Ephemeroptera), North of Mexico; Version 2. Joint Aquatic Science meeting, Portland, OR. Unpublished workshop manual. 1-176.
Merritt R.W., Cummins, K.W., and Berg, M.B. 2019. An Introduction to the Aquatic Insects of North America (Fifth Edition). Kendall/Hunt Publishing Company.