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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

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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CalebBoyle has attached these 2 pictures to aid in identification. The message is below.
Charlotte, NC

Posts: 11
CalebBoyle on May 23, 2007May 23rd, 2007, 2:27 pm EDT
Hi guys,

I found this female mayfly near where I live and wanted to see what you all thought about it. It was found in gaston county (near Charlotte) in North Carolina. When I first glanced at it I thought it must be some kind of drake, but quickly realized it couldn't be. There are only 2 tails and this monster is 36-37mm long. I have never heard of Hexagenia in North Carolina, but isn't this a H. limbata? If so what records are there for NC hatches and how common are they? Most of the pictures that I have seen of limbata have darker markings on the abdomen, but then what other mayfly is this size other than a Litobrancha recurvata?

Caleb Boyle
Taxon's profile picture
Site Editor
Plano, TX

Posts: 1311
Taxon on May 23, 2007May 23rd, 2007, 3:03 pm EDT
Nice photos, Caleb. You have (3) Hexagenia species in N. Carolina, H. atrocaudata, H. bilineata, and H. limbata. However, given its size and date of emergence, it is almost certainly H. limbata. Incidentally, notice the characteristic vestigal terminal filament! That is one I've been saving for you, Gonzo.
Best regards,
Roger Rohrbeck
Troutnut's profile picture
Bellevue, WA

Posts: 2758
Troutnut on May 23, 2007May 23rd, 2007, 3:20 pm EDT
It's H. limbata. That's a widely variable species, and back in the 1940s it was actually broken into about 6 sub-species with different looks and geographic ranges. The sub-species aren't considered valid anymore (it's all just one undivided species now, I think) but the point is that H. limbata comes in many flavors.

Somebody recently emailed me asking me to identify one from Texas, too.
Jason Neuswanger, Ph.D.
Troutnut and salmonid ecologist
Site Editor
"Bear Swamp," PA

Posts: 1681
GONZO on May 23, 2007May 23rd, 2007, 4:08 pm EDT
Roger--Thanks for the terminal filament reference. You've been saving that one for a while!

Caleb--Beautiful specimen! The variability in color/markings that Jason mentions always amazes me when I view specimens of this transcontinental species.
Charlotte, NC

Posts: 11
CalebBoyle on May 24, 2007May 24th, 2007, 8:43 am EDT
Thanks guys for the confirmations-- I had just never heard about limbata this far south. I agree Gonzo, I have seen some photos of color variations that are really different.


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