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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.

Dorsal view of a Ephemerella mucronata (Ephemerellidae) Mayfly Nymph from the Yakima River in Washington
This is an interesting one. Following the keys in Merritt R.W., Cummins, K.W., and Berg, M.B. (2019) and Jacobus et al. (2014), it keys clearly to Ephemerella. Jacobus et al provide a key to species, but some of the characteristics are tricky to interpret without illustrations. If I didn't make any mistakes, this one keys to Ephemerella mucronata, which has not previously been reported any closer to here than Montana and Alberta. The main character seems to fit well: "Abdominal terga with prominent, paired, subparallel, spiculate ridges." Several illustrations or descriptions of this holarctic species from the US and Europe seem to match, including the body length, tarsal claws and denticles, labial palp, and gill shapes. These sources include including Richard Allen's original description of this species in North America under the now-defunct name E. moffatae in Allen RK (1977) and the figures in this description of the species in Italy.
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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Posts: 17
Earlfishman on Apr 11, 2007April 11th, 2007, 5:28 pm EDT
Find a used copy of Wiggin's "trichoptera larvae of north america" or some similar title. It is the best guide to get to genus for all the caddis you may run across
Schuylkill County, PA.

Posts: 109
Quillgordon on Apr 12, 2007April 12th, 2007, 2:14 am EDT
Found this.......... FWIW........

Wiggins, G. Larvae of the North American Caddisfly Genera (Trichoptera). 2nd ed. Toronto and Buffalo, NY: University of Toronto Press, 1996.

Flyfishing is a state of mind! .............. Q.g.

Site Editor
"Bear Swamp," PA

Posts: 1681
GONZO on Apr 12, 2007April 12th, 2007, 2:32 am EDT
Hi Earl (and John),

Earl, I'm assuming that you're referring to my tentative guess that this might be Pycnopsyche. Actually, it's not that I'm not aware of the more comprehensive keys or where to find them, it's just that I rarely have more than bits and pieces (along with my own experience) to call upon on the spur of the moment. I usually won't comment on a specimen if I'm not pretty sure that it's something I'm familiar with. And I realize that my methods are not scientific.

However, Limnephilids always drive me a little crazy. If you have the Wiggins keys on hand, I'd be interested to know what you can make of this specimen.
Posts: 17
Earlfishman on Apr 17, 2007April 17th, 2007, 4:55 am EDT

Your right, this specimen is Pycnopsyche sp. The key characters that can lead you there are all visible in the above photos. Abdominal gills are single; there is an elongate sclerite posterior to the lateral hump that can be seen in one of the photos; and finally the metanotal sa1 sclerites are not fused on the mid-dorsal line. The case is also fairly characteristic of Pycnopsyche. The only genus that is really confusable is Hydatophylax sp., but in most cases the metanotal sa1 sclerites are fused on that bug.

Those are the characters, but the fact is it just looks like Pycnopsyche.

Hope that helps.

Site Editor
"Bear Swamp," PA

Posts: 1681
GONZO on Apr 17, 2007April 17th, 2007, 5:15 am EDT
Thanks, Earl. :)

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