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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
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.

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.
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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Female Baetidae (Blue-Winged Olive) Mayfly Spinner Pictures

This species is probably in Centroptilum, Cloeon, or Procloeon. I captured this spinner on the same night as a dun which is probably of the same species.

Lateral view of a Female Baetidae (Blue-Winged Olive) Mayfly Spinner from the West Branch of Owego Creek in New York
Female Baetidae (Blue-Winged Olive) Mayfly Spinner from the West Branch of Owego Creek in New York
Female Baetidae (Blue-Winged Olive) Mayfly Spinner from the West Branch of Owego Creek in New York
This picture shows the shape of the costal process on the hind wing pretty well.

Female Baetidae (Blue-Winged Olive) Mayfly Spinner from the West Branch of Owego Creek in New York
Female Baetidae (Blue-Winged Olive) Mayfly Spinner from the West Branch of Owego Creek in New York
Female Baetidae (Blue-Winged Olive) Mayfly Spinner from the West Branch of Owego Creek in New York
Female Baetidae (Blue-Winged Olive) Mayfly Spinner from the West Branch of Owego Creek in New York
Female Baetidae (Blue-Winged Olive) Mayfly Spinner from the West Branch of Owego Creek in New York
Ruler view of a Female Baetidae (Blue-Winged Olive) Mayfly Spinner from the West Branch of Owego Creek in New York The smallest ruler marks are 1 mm.
Ventral view of a Female Baetidae (Blue-Winged Olive) Mayfly Spinner from the West Branch of Owego Creek in New York
Dorsal view of a Female Baetidae (Blue-Winged Olive) Mayfly Spinner from the West Branch of Owego Creek in New York
This false-color image of the clear wings shows all the veins.

Female Baetidae (Blue-Winged Olive) Mayfly Spinner from the West Branch of Owego Creek in New York
Female Baetidae (Blue-Winged Olive) Mayfly Spinner from the West Branch of Owego Creek in New York

This mayfly was collected from the West Branch of Owego Creek in New York on August 9th, 2006 and added to Troutnut.com by Troutnut on August 11th, 2006.

Discussions of this Spinner

No Help
Posted by Taxon on Aug 11, 2006
Last reply on Aug 11, 2006 by Taxon
Jason-

The single detached intercalaries in the fore wing would limit the choices to the genera you suggest. The sharply pointed costal projection and single longitudinal vein in the hind wing probably narrow it to a single species. Unfortunately, none of the Baetidae hind wing illustrations to which I have access show either that sharply pointed of a projection or the single longitudinal vein, let alone in combination with one another.
Anyone want to weigh on on the ID here?
Posted by Troutnut on Aug 11, 2006
Last reply on Aug 11, 2006 by Troutnut
I can't follow the key in Merritt & Cummins very far since it's not a male spinner. The sharp costal process could be a good hint. Anybody know which genus or species this is?

Start a Discussion of Spinner

Female Baetidae (Blue-Winged Olive) Mayfly Spinner Pictures

Collection details
Location: West Branch of Owego Creek, New York
Date: August 9th, 2006
Added to site: August 11th, 2006
Author: Troutnut
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