Header image
Enter a name
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.
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.

Freepow has attached these 5 pictures. The message is below.
menomonie, WI

Posts: 83
Freepow on Jun 5, 2008June 5th, 2008, 5:44 pm EDT
I browsed through the insect pictures but I am not very good at what things I am looking for that separate the different types of bugs. Can anyone tell me what this is??? Also, pics of a nice brookie and brown.
"I fish...because I suspect that men are going along this way for the last time, and I for one don't want to waste the trip..."
Schuylkill County, PA.

Posts: 109
Quillgordon on Jun 5, 2008June 5th, 2008, 11:49 pm EDT
Nice photos...........
I would guess 'March brown'.... not being a real biologist!
Flyfishing is a state of mind! .............. Q.g.

Wiflyfisher's profile picture

Posts: 622
Wiflyfisher on Jun 5, 2008June 5th, 2008, 11:54 pm EDT
Definitely looks like Stenonema vicarium (new name Maccaffertium vicarium) - also called March Brown. Nice photos!

menomonie, WI

Posts: 83
Freepow on Jun 6, 2008June 6th, 2008, 3:15 am EDT
Definitely looks like a March Brown to me too. That was quick. Thanks guys.
"I fish...because I suspect that men are going along this way for the last time, and I for one don't want to waste the trip..."

Quick Reply

Related Discussions

Last Reply
Jun 2, 2007
by Dryfly
Troutnut.com is copyright © 2004-2024 (email Jason). privacy policy