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.
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Caddisfly Genus Pycnopsyche (Great Autumn Brown Sedges)
Genus Range
Egg-Laying behavior
Time of day: Nighttime; sometimes dusk or early morning
Larva & pupa biology
Diet: Decaying leaves
Shelter type: Twigs arranged lengthwise
Their life cycle is completely synchronized with this food source -- the eggs hatch in the fall, just as the deciduous trees are shedding their foliage; the larvae feed and grow throughout the winter and spring, until early summer when the high water flushes away the accumulations of decaying leaves; the larvae enter diapause, a quiescent period, sealing off their cases, once their food source is diminished; they remain in this inactive state until they pupate in late summer; emergence, mating, and egg laying occurs in early fall, producing a new generation in time for the next input of leaves.
Specimens of the Caddisfly Genus Pycnopsyche
3 Larvae
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.
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.
This specimen appears to be of the same species as this one collected in the same spot two months earlier. The identification of both is tentative. This one suffered some physical damage before being photographed, too, so the colors aren't totally natural. I was mostly photographing it to test out some new camera setting idea, which worked really well for a couple of closeups.
Discussions of Pycnopsyche
Great Autumn Brown Sedges on Potomac River
3 replies
Posted by BrettB on Oct 2, 2008
Last reply on Oct 3, 2008 by GONZO
Came in to work today and noted several large Autumn sedges on doors facing river(18mm wing-to-head and 34mm total w/ antennae). Though more brownish-rusty than I remember them being, I'm relatively certain it is a Pycnopsyche due to the size, timing and dark markings near the rear mid-wing (sort of looks like a yin-yang symbol). Does anyone know of a good emerger fly for this hatch? I'm assuming it emerges in the evening through early morning. I may tie up some size 8 rusty elk hair caddis for adult imitations. Big bugs!
Start a Discussion of Pycnopsyche
References
- LaFontaine, Gary. 1981. Caddisflies. The Lyons Press.
- Swisher, Doug and Carl Richards. 2000. Selective Trout. The Lyons Press.
Caddisfly Genus Pycnopsyche (Great Autumn Brown Sedges)
Taxonomy
14 species (Pycnopsyche aglonus, Pycnopsyche antica, Pycnopsyche circularis, Pycnopsyche conspersa, Pycnopsyche divergens, Pycnopsyche flavata, Pycnopsyche gentilis, Pycnopsyche indiana, Pycnopsyche limbatus, Pycnopsyche luculentus, Pycnopsyche rossi, Pycnopsyche sonso, Pycnopsyche subfasciata, and Pycnopsyche virginica) aren't included.