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.

A beautiful braided reach of the Sag River, with the Philip Smith Mountains in the Arctic National Wildlife Refuge (ANWR) in the background.

From the Sagavanirktok River in Alaska

Stream photos

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Neoleptophlebia Mayfly Nymph Neoleptophlebia Mayfly Nymph

Dorsal view of a Neoleptophlebia (Leptophlebiidae) Mayfly Nymph from the Yakima River in Washington

Some characteristics from the microscope images for the tentative species id: The postero-lateral projections are found only on segment 9, not segment 8. Based on the key in Jacobus et al. (2014), it appears to key to Neoleptophlebia adoptiva or Neoleptophlebia heteronea, same as this specimen with pretty different abdominal markings. However, distinguishing between those calls for comparing the lengths of the second and third segment of the labial palp, and this one (like the other one) only seems to have two segments. So I'm stuck on them both. It's likely that the fact that they're immature nymphs stymies identification in some important way.

10 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.

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Isoperla (Stripetails and Yellow Stones) Stonefly Adult Pictures

Several stoneflies of this species were flying around a small stream last night. I tied on a brown drake imitation of about the right size/color to approximate these stones, and was rewarded with a hard-fighting 17-inch brown trout.

Lateral view of a Isoperla (Perlodidae) (Stripetails and Yellow Stones) Stonefly Adult from Cayuta Creek in New York

Ventral view of a Isoperla (Perlodidae) (Stripetails and Yellow Stones) Stonefly Adult from Cayuta Creek in New York

Dorsal view of a Isoperla (Perlodidae) (Stripetails and Yellow Stones) Stonefly Adult from Cayuta Creek in New York

Isoperla (Perlodidae) (Stripetails and Yellow Stones) Stonefly Adult from Cayuta Creek in New York

Ruler view of a Isoperla (Perlodidae) (Stripetails and Yellow Stones) Stonefly Adult from Cayuta Creek in New York The smallest ruler marks are 1 mm.

This stonefly was collected from Cayuta Creek in New York on July 7th, 2006 and added to Troutnut.com by Troutnut on July 8th, 2006.

Discussions of this Adult

Chloroperlidae

3 replies

Posted by Teamrenna on Jun 12, 2008

Last reply on Sep 9, 2008 by GONZO

Edit: Post removed

Family ID for this one?

2 replies

Posted by Troutnut on Jul 30, 2006

Last reply on Jul 30, 2006 by Troutnut

I haven't had time to look through my stonefly keys yet. It's a pretty small yellow fly, so I'm guessing Chloroperlidae, though I have no real reason to rule out Perlodidae.

I've saved it in alcohol to key out under a microscope at some later date, but it'll be a while before I have time.

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References

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.