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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.

Case view of a Pycnopsyche guttifera (Limnephilidae) (Great Autumn Brown Sedge) Caddisfly Larva from the Yakima River in Washington
It's only barely visible in one of my pictures, but I confirmed under the microscope that this one has a prosternal horn and the antennae are mid-way between the eyes and front of the head capsule.

I'm calling this one Pycnopsyche, but it's a bit perplexing. It seems to key definitively to at least Couplet 8 of the Key to Genera of Limnephilidae Larvae. That narrows it down to three genera, and the case seems wrong for the other two. The case looks right for Pycnopsyche, and it fits one of the key characteristics: "Abdominal sternum II without chloride epithelium and abdominal segment IX with only single seta on each side of dorsal sclerite." However, the characteristic "metanotal sa1 sclerites not fused, although often contiguous" does not seem to fit well. Those sclerites sure look fused to me, although I can make out a thin groove in the touching halves in the anterior half under the microscope. Perhaps this is a regional variation.

The only species of Pycnopsyche documented in Washington state is Pycnopsyche guttifera, and the colors and markings around the head of this specimen seem to match very well a specimen of that species from Massachusetts on Bugguide. So I am placing it in that species for now.

Whatever species this is, I photographed another specimen of seemingly the same species from the same spot a couple months later.
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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Sekod has attached these 4 pictures to aid in identification. The message is below.
Sekod
Sekod's profile picture
New London, NC

Posts: 1
Sekod on Aug 26, 2019August 26th, 2019, 9:49 pm EDT
The larger fly had 2 long tails and one very short tail (almost a stub) in between the longer ones. The smaller one had 2 tails. Warmwater river (Little River) in the Piedmont of North Carolina. ID help? Thank you.
Taxon
Taxon's profile picture
Site Editor
Plano, TX

Posts: 1311
Taxon on Aug 27, 2019August 27th, 2019, 6:54 am EDT
Hi Jonathan-

I believe those mayfly subimagoes are both of genus Hexagenia. The larger one is a female, and the smaller one is a male.
Best regards,
Roger Rohrbeck
www.FlyfishingEntomology.com

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