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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.

Lateral view of a Onocosmoecus (Limnephilidae) (Great Late-Summer Sedge) Caddisfly Larva from the Yakima River in Washington
This specimen keys pretty easily to Onocosmoecus, and it closely resembles a specimen from Alaska which caddis expert Dave Ruiter recognized as this genus. As with that specimen, the only species in the genus documented in this area is Onocosmoecus unicolor, but Dave suggested for that specimen that there might be multiple not-yet-distinguished species under the unicolor umbrella and it would be best to stick with the genus-level ID. I'm doing the same for this one.
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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Ephemerella needhami (Little Dark Hendrickson) Mayfly Nymph Pictures

I took quite a few notes at the microscope when I collected this specimen. They're attached to the appropriate pictures.

I found this specimen in the same collection as a similar one. Since I only have strange views of this one, it's possible that they're actually the same specimen and I somehow confused my picture-ordering and got the impression that they're different nymphs.

There are fairly prominent tubercles on abdominal segments 2-8, and none on segments 1, 9, and 10, not even at high magnification.

Ephemerella needhami (Ephemerellidae) (Little Dark Hendrickson) Mayfly Nymph from the Namekagon River in Wisconsin
There are postero-lateral projections on adominal segments 4-9.

Dorsal view of a Ephemerella needhami (Ephemerellidae) (Little Dark Hendrickson) Mayfly Nymph from the Namekagon River in Wisconsin
Ventral view of a Ephemerella needhami (Ephemerellidae) (Little Dark Hendrickson) Mayfly Nymph from the Namekagon River in Wisconsin
The maxillary palp is 3-segmented and, in this photo, rather blurry.

Ephemerella needhami (Ephemerellidae) (Little Dark Hendrickson) Mayfly Nymph from the Namekagon River in Wisconsin
The fore tarsal claw has 7 denticles.

Ephemerella needhami (Ephemerellidae) (Little Dark Hendrickson) Mayfly Nymph from the Namekagon River in Wisconsin

This mayfly was collected from the Namekagon River in Wisconsin on June 8th, 2005 and added to Troutnut.com by Troutnut on May 26th, 2006.


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Ephemerella needhami (Little Dark Hendrickson) Mayfly Nymph Pictures

Collection details
Location: Namekagon River, Wisconsin
Date: June 8th, 2005
Added to site: May 26th, 2006
Author: Troutnut
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