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Lateral view of a Female Hexagenia limbata (Ephemeridae) (Hex) Mayfly Dun from the Namekagon River in Wisconsin
Hex Mayflies
Hexagenia limbata

The famous nocturnal Hex hatch of the Midwest (and a few other lucky locations) stirs to the surface mythically large brown trout that only touch streamers for the rest of the year.

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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Argia Damselfly Nymph Pictures

My friend Willy captured this early instar damselfly nymph and brought it to me for identification. It is more robust and stocky at this early stage than the spindly appearance of the later instars, and its appearance is less familiar.

Argia (Coenagrionidae) Damselfly Nymph from Fall Creek in New York
Dorsal view of a Argia (Coenagrionidae) Damselfly Nymph from Fall Creek in New York
Argia (Coenagrionidae) Damselfly Nymph from Fall Creek in New York

This damselfly was collected from Fall Creek in New York on August 28th, 2005 and added to Troutnut.com by Troutnut on April 14th, 2006.

Discussions of this Nymph

What size are damselflies?
1 replies
Posted by Adirman on Jun 28, 2012
Last reply on Jun 28, 2012 by Entoman
Whenever I go up to the Adirondacks in midsummer to fish, I always observe alot of damselflies aroundand know the trout take them, at least occasionally, because I've watched them do it. I was wondering what size the nymphs were and if a black stone fly pattern of correct size might imitate the nymph well enough.

Thanks!!

Adirman
irradecant blue damselfly
Posted by Mwmeci on Jul 3, 2008
Last reply on Jul 3, 2008 by Mwmeci
The trout in Wisconsin on July 3, 2008 were eating the fly's as they emerged. Gosh they make a ruckus as they took to the air. They only emerged under a very low bridge, not upstream or downstream from the bridge. I've never witnessed this before.
Argia characters
Posted by DMM on Nov 26, 2006
Last reply on Nov 26, 2006 by DMM
One reason I think it's Argia, is that this genus is characteristically "stubby" and "robust" through the last instar. Without verification, I think it is the stubbiest of the Zygoptera.
Genus ID
Posted by DMM on Nov 18, 2006
Last reply on Nov 18, 2006 by DMM
May be Argia, detailed pictures of the prementum are always good for the ID of Odonata. Odonata can be tricky in general though, so the more details the better.

Start a Discussion of Nymph

Argia Damselfly Nymph Pictures

Collection details
Location: Fall Creek, New York
Date: August 28th, 2005
Added to site: April 14th, 2006
Author: Troutnut
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