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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 Zapada cinctipes (Nemouridae) (Tiny Winter Black) Stonefly Nymph from the Yakima River in Washington
Nymphs of this species were fairly common in late-winter kick net samples from the upper Yakima River. Although I could not find a key to species of Zapada nymphs, a revision of the Nemouridae family by Baumann (1975) includes the following helpful sentence: "2 cervical gills on each side of midline, 1 arising inside and 1 outside of lateral cervical sclerites, usually single and elongate, sometimes constricted but with 3 or 4 branches arising beyond gill base in Zapada cinctipes." This specimen clearly has the branches and is within the range of that species.
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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Stonefly Species Agnetina capitata (Golden Stones)

This is the most important Perlidae species in the East.

Where & when

Time of year : June and July

In 35 records from GBIF, adults of this species have mostly been collected during June (46%), May (31%), July (11%), and August (6%).

In 2 records from GBIF, this species has been collected at elevations of 680 and 2723 ft.

Species Range

Hatching behavior

Time of day : Morning

Egg-Laying behavior

Time of day: Dusk

Identification

To determine whether a specimen of Agnetina belongs to Agnetina capitata, use the Key to Species of Agnetina Nymphs or Key to Species of Agnetina Adults.

Specimens of the Stonefly Species Agnetina capitata

2 Male Adults
2 Nymphs

Discussions of Agnetina capitata

Cultus verticalis?
8 replies
Posted by DOS on Mar 31, 2009
Last reply on Apr 1, 2009 by Troutnut
Hello gentlemen,

Again I come to you for guidance...

While monkeying around today in the aquarium, I flipped over a rock and this guy came scurrying out. I have recently been studying A. capitata and realized immediately that this might be a different species. Until now, I had thought that A. capitata was the only "golden stone" I had collected here in WNY to date, however I guess now I have one more under my belt! Is it weird that this excites me??

When I do my collecting on the stream and bring the insects home, I attempt to snap a pic of each before I place them in the aquarium, sort of a photographic inventory. This guy must have been hiding somewhere and was overlooked in that process.

So, anyone want to go out on a limb and confirm this as Cultus verticalis? Other than a measured length of 19mm, I can't really offer up any identifying features that aren't visible in the pictures. I don't have access to the M&C key. Anyone know if its posted online? I'll search my school library in a moment.

If it is C. verticalis, I've noticed that neither genus or species appear on the USGS Stoneflies of New York list. I see that Jason originally coded his specimen to the genus Arcynopteryx which contains three species. Again, none appear anywhere near WNY on the USGS list. Any other ideas of a possible alternative ID? http://www.npwrc.usgs.gov/resource/distr/insects/sfly/ny/toc.htm

If its not on the list, anyone know if and how I can submit my findings? Also, what is your experience with the USGS lists in regards to its accuracy and completeness? This and other instances have me thinking there are some holes in the data.

Unfortunately, this specimen perished as I was photographing it. I was hoping it would survive so that it might emerge and I could get snap photos as an adult. Tomorrow I'm heading to the location where I collected him to see if I can determine abundance in relation to A. capitata, as obviously the share the same lotic environment.

Thanks in advance!







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Start a Discussion of Agnetina capitata

References

Stonefly Species Agnetina capitata (Golden Stones)

Taxonomy
Species Range
Resources
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