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.

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)

Onocosmoecus (Great Late-Summer Sedge) Caddisfly Larva Onocosmoecus (Great Late-Summer Sedge) Caddisfly Larva

Lateral view of a Onocosmoecus (Limnephilidae) (Great Late-Summer Sedge) Caddisfly Larva from the Yakima River in Washington

This specimen keys pretty easily to Onocosmoecus, and it closely resembles a specimen from Alaska which caddis expert Dave Ruiter recognized as this genus. As with that specimen, the only species in the genus documented in this area is Onocosmoecus unicolor, but Dave suggested for that specimen that there might be multiple not-yet-distinguished species under the unicolor umbrella and it would be best to stick with the genus-level ID. I'm doing the same for this one.

9 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 Leucrocuta hebe (Little Yellow Quill) Mayfly Dun Pictures

I found this dun on the same piece of stream as a similar spinner, probably of the same species.

Female Leucrocuta hebe (Heptageniidae) (Little Yellow Quill) Mayfly Dun from Mystery Creek #43 in New York

Lateral view of a Female Leucrocuta hebe (Heptageniidae) (Little Yellow Quill) Mayfly Dun from Mystery Creek #43 in New York

Dorsal view of a Female Leucrocuta hebe (Heptageniidae) (Little Yellow Quill) Mayfly Dun from Mystery Creek #43 in New York

Ventral view of a Female Leucrocuta hebe (Heptageniidae) (Little Yellow Quill) Mayfly Dun from Mystery Creek #43 in New York

Ruler view of a Female Leucrocuta hebe (Heptageniidae) (Little Yellow Quill) Mayfly Dun from Mystery Creek #43 in New York The smallest ruler marks are 1 mm.

This mayfly was collected from Mystery Creek #43 in New York on September 19th, 2006 and added to Troutnut.com by Troutnut on October 4th, 2006.

Discussions of this Dun

Looks like Leucrocuta

Posted by GONZO on Oct 6, 2006

Last reply on Oct 6, 2006 by GONZO

Haven't checked any keys to verify, but most of the little late-season Cahill-looking duns are Leucrocuta. If I had to guess at the species, I'd say hebe (Little Yellow Quill). It is probably the most common L. spp. in the East and has a long hatching period that extends well into the fall.

I would also agree that the spinner you photographed is the same species.

Start a Discussion of Dun