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Artistic view of a Male Pteronarcys californica (Pteronarcyidae) (Giant Salmonfly) Stonefly Adult from the Gallatin River in Montana
Salmonflies
Pteronarcys californica

The giant Salmonflies of the Western mountains are legendary for their proclivity to elicit consistent dry-fly action and ferocious strikes.

Dorsal view of a Setvena wahkeena (Perlodidae) (Wahkeena Springfly) Stonefly Nymph from Mystery Creek #199 in Washington
As far as I can tell, this species has only previously been reported from one site in Oregon along the Columbia gorge. However, the key characteristics are fairly unmistakable in all except for one minor detail:
— 4 small yellow spots on frons visible in photos
— Narrow occipital spinule row curves forward (but doesn’t quite meet on stem of ecdysial suture, as it's supposed to in this species)
— Short spinules on anterior margin of front legs
— Short rposterior row of blunt spinules on abdominal tergae, rather than elongated spinules dorsally
I caught several of these mature nymphs in the fishless, tiny headwaters of a creek high in the Wenatchee Mountains.
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.
Troutnut is a project started in 2003 by salmonid ecologist Jason "Troutnut" Neuswanger to help anglers and fly tyers unabashedly embrace the entomological side of the sport. Learn more about Troutnut or support the project for an enhanced experience here.

Male Hexagenia atrocaudata (Late Hex) Mayfly Spinner Pictures

Male Hexagenia atrocaudata (Ephemeridae) (Late Hex) Mayfly Spinner from the Namekagon River in Wisconsin
Dorsal view of a Male Hexagenia atrocaudata (Ephemeridae) (Late Hex) Mayfly Spinner from the Namekagon River in Wisconsin
Ruler view of a Male Hexagenia atrocaudata (Ephemeridae) (Late Hex) Mayfly Spinner from the Namekagon River in Wisconsin The smallest ruler marks are 1 mm.
Artistic view of a Male Hexagenia atrocaudata (Ephemeridae) (Late Hex) Mayfly Spinner from the Namekagon River in Wisconsin
Male Hexagenia atrocaudata (Ephemeridae) (Late Hex) Mayfly Spinner from the Namekagon River in Wisconsin
Ventral view of a Male Hexagenia atrocaudata (Ephemeridae) (Late Hex) Mayfly Spinner from the Namekagon River in Wisconsin
Male Hexagenia atrocaudata (Ephemeridae) (Late Hex) Mayfly Spinner from the Namekagon River in Wisconsin
Male Hexagenia atrocaudata (Ephemeridae) (Late Hex) Mayfly Spinner from the Namekagon River in Wisconsin
Male Hexagenia atrocaudata (Ephemeridae) (Late Hex) Mayfly Spinner from the Namekagon River in Wisconsin
Male Hexagenia atrocaudata (Ephemeridae) (Late Hex) Mayfly Spinner from the Namekagon River in Wisconsin
Male Hexagenia atrocaudata (Ephemeridae) (Late Hex) Mayfly Spinner from the Namekagon River in Wisconsin
Male Hexagenia atrocaudata (Ephemeridae) (Late Hex) Mayfly Spinner from the Namekagon River in Wisconsin
Male Hexagenia atrocaudata (Ephemeridae) (Late Hex) Mayfly Spinner from the Namekagon River in Wisconsin
Male Hexagenia atrocaudata (Ephemeridae) (Late Hex) Mayfly Spinner from the Namekagon River in Wisconsin

This mayfly was collected from the Namekagon River in Wisconsin on July 24th, 2005 and added to Troutnut.com by Troutnut on April 15th, 2006.

Discussions of this Spinner

mayflysneed
1 replies
Posted by Irdawson on Dec 2, 2010
Last reply on Dec 2, 2010 by Taxon
need places in florida that have mayflies,lakes or rivers.thanksin advance
Nice
Posted by Botebearing on Jan 20, 2010
Last reply on Jan 20, 2010 by Botebearing
really nice pictures.Garden Light
Mayflies
2 replies
Posted by Fishcraze on May 27, 2009
Last reply on May 31, 2009 by Trtklr
I know in North Alabama these flies usually hatch in Jun. What climate/water temperatures are required for hatching? Does it normally have to be dry/no rain for a week?

Thanks to anyone who can answer these questions. I promised my 12 year old, I was going to take him this year and I'm trying to plan my leave at the closest possible time.

Fishcraze

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Male Hexagenia atrocaudata (Late Hex) Mayfly Spinner Pictures

Collection details
Location: Namekagon River, Wisconsin
Date: July 24th, 2005
Added to site: April 15th, 2006
Author: Troutnut
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