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.

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.

DayTripper has attached these 3 pictures to aid in identification. The message is below.
Top
DayTripper
DayTripper's profile picture
Northern MI

Posts: 70
DayTripper on May 30, 2013May 30th, 2013, 4:17 pm EDT
Collected this guy on a northern Michigan trout pond last night. Found it struggling on the surface in the middle of the lake. Not sure if it just emerged or if it fell in while flying over. Anyone know how to tell what the sex is on these? I am also curious what genus/species it might be. Thanks!
Sayfu
Posts: 560
Sayfu on May 30, 2013May 30th, 2013, 4:37 pm EDT

I don't think they ever emerge out of the water. Don't all craneflies pupate, and emerge on land? Always scary to say "all".
DayTripper
DayTripper's profile picture
Northern MI

Posts: 70
DayTripper on May 30, 2013May 30th, 2013, 4:59 pm EDT
According to the crane fly page here on troutnut,

"Hatching Behavior
Craneflies pupate for one to three weeks. The species which do so in the water then swim to the surface to emerge in the style of caddisflies, and are presumably vulnerable to trout, though I have not read about good fishing during these events.

Swisher and Richards in Selective Trout say the larvae all crawl out of the water to pupate, conflicting with the above account. There are so many species that it seems likely both behaviors occur in some species."

I checked a half dozen other websites and all say that they crawl onto land. In Matching the Hatch, Schweibert references species that pupate and emerge in the water (late mornings). McCafferty also references that there are species that pupate in water, but doesn't go into much detail.
Taxon
Taxon's profile picture
Site Editor
Plano, TX

Posts: 1311
Taxon on May 30, 2013May 30th, 2013, 5:27 pm EDT
DayTripper-

Anyone know how to tell what the sex is on these?

The terminal adominal segment of a male is expanded and rounded, whereas the female's tapers to a point. So, I believe your photos are of a female.
Best regards,
Roger Rohrbeck
www.FlyfishingEntomology.com
Creno
Grants Pass, OR

Posts: 302
Creno on May 30, 2013May 30th, 2013, 5:38 pm EDT
Definitely a female - males have much more complex parts. Is that a metric or english rule? I see the 10ths but I have an english rule in 10ths so thought I would check. If english it is likely one of the Tipula. If metric I suspect there are some other genera that large. Tipula are not typically pond forms, more likely the marshy areas surrounding the pond.
DayTripper
DayTripper's profile picture
Northern MI

Posts: 70
DayTripper on May 30, 2013May 30th, 2013, 5:44 pm EDT
Thanks, guys!

Its a metric ruler, I measured this one at a smidge under 25mm.
Crepuscular
Crepuscular's profile picture
Boiling Springs, PA

Posts: 920
Crepuscular on Jun 1, 2013June 1st, 2013, 5:31 am EDT
Ok I'm definitely not an expert but the elongated abdomen of this female narrows it down somewhat and after running it through the key, I'm somewhat confident in my determination... Definitely Tipulidae, probably Tipula dorsimacula. Pretty common from what I read and very widespread distribution. One generation a year. If it is T. dorsimacula, it is a terrestrial species (the ovipositor is a clue to that) that probably just fell into the water.

Quick Reply

Related Discussions

Topic
Replies
Last Reply
6
Jun 10, 2007
by Invicta
6
Jun 11, 2009
by GONZO
Troutnut.com is copyright © 2004-2024 (email Jason). privacy policy