Blue-winged Olives
Baetis
Tiny Baetis mayflies are perhaps the most commonly encountered and imitated by anglers on all American trout streams due to their great abundance, widespread distribution, and trout-friendly emergence habits.
Featured on the forum
This seems to be a young larva of Limnephilus. Although not clear in the picture, several ventral abdominal segments have chloride epithelia.
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.
Mayfly Family Ephemeridae (Hexes and Big Drakes)
Several great superhatches come from this family. The Green, Yellow, and Brown Drakes all belong to the Ephemera genus. Hexagenia and Litobrancha contain the largest mayflies in North America and present legendary fly fishing opportunities, especially the famed "Hex hatch" of Hexagenia limbata.
Family Range
Nymph biology
Nymphs of this family are nocturnal and their pale bodies sensitive to the sunlight. They build U-shaped burrows less than six inches into the stream bottom, where they feed on microorganisms in the fertile sediment. They come out of these burrows to molt up to 30 times throughout their development. They require sediment of a particular density, soft enough for them to dig burrows but hard enough that the burrows don't collapse.It common in this family for nymphs to live 2-3 years before emerging. This is very unusual among mayflies.
Identification
To determine whether a specimen of Ephemeroptera belongs to Ephemeridae, use the Key to Families of Mayfly Nymphs or Key to Families of Mayfly Duns and Spinners.
Specimens of the Mayfly Family Ephemeridae
6 Male Duns
These photos were contributed by Spencer Vanderhoof.
This species is very abundant in Flathead and Whitefish Lakes with a smaller population in lakes of the Swan River Drainage, and a few in Lake McDonald in Glacier Park. This species usually emerges along with Ephemera simulans.
Male and female duns.
11 Female Duns
This female Hex dun emerged around 11 pm, one of relatively few on the water as I rushed back to the truck to beat an approaching thunderstorm. Her tails in reality were longer than shown in the picture, but they broke off.
For years after I started this website, I was eagerly hoping to find a green drake to add to the collection, but I was never in the right part of the world at the right time. It finally happened on June 1st, 2007.
This yellow drake dun hatched out of my aquarium over a month before her brethren in the wild are slated to emerge. She seems a bit small, and that might be the reason.
I found this lone Hexagenia atrocaudata dun fluttering by herself on the surface of a small, still stretch of river one evening as I paddled home from fishing for smallmouths in the warm August weather.
These photos were contributed by Spencer Vanderhoof.
10 Male Spinners
This spinner was the only member of its species I saw all night during an incredibly thick and tricky mixed hatch on Penn's Creek a few days before the real start of its famous green drake hatch.
I found this spinner and a few of his friends bobbing above the river amidst a snowstorm hatch of white Ephoron flies.
This one hatched in the middle of July, which is very late for this species.
These photos were contributed by Spencer Vanderhoof.
4 Female Spinners
I found this female spinner ovipositing in a small stream. She came along while I was playing a trout -- every good bug seemed to do that last night! I didn't have my bug net, so I caught the trout in my landing net, released the trout, and caught the mayfly in my landing net. Her wing got a bit messed up from that.
I found this Hexagenia limbata spinner on a gas station in upstate New York, not a region known for heavy hatches of this species.
15 Nymphs
This nymph is about an inch long.
This medium-instar nymph is about an inch long.
7 Streamside Pictures of Ephemeridae Mayflies:
I didn't manage to collect a nymph, but here's the hollow shuck left over from an emerged dun, showing the basic pattern of the nymph.
In this picture: Mayfly Species Ephemera guttulata (Green Drake).
Some Hexagenia limbata duns and several smaller mayflies litter the surface of this river during a Hex emergence.
In this picture: Mayfly Species Hexagenia limbata (Hex).
A huge swarm of Hexagenia limbata spinners gathers over the riffle.
In this picture: Mayfly Species Hexagenia limbata (Hex).
Giant Hexagenia limbata spinners leave ghostly trails around the glow of a full moon.
In this picture: Mayfly Species Hexagenia limbata (Hex).
This is the skin a brown drake dun shed when it molted into a spinner. Many of these were on the surface one afternoon, having been blown in after the flies molted on overhanging alders. They were our most noticeable sign of an intense brown drake hatch the previous night and a spinner fall to come.
In this picture: Mayfly Species Ephemera simulans (Brown Drake).
Two Ephemera simulans (Brown Drake) spinners hang from tree leaves along the river. It's worthwhile to look for these in afternoons during the Brown Drake hatch, because their presence may reveal the best place to fish in the evening.
In this picture: Mayfly Species Ephemera simulans (Brown Drake).
Spent Hex spinners on a small stream the morning after the hatch.
In this picture: Mayfly Species Hexagenia limbata (Hex).
3 Underwater Pictures of Ephemeridae Mayflies:
A crayfish chews on a Hexagenia limbata nymph shortly after a small Hex emergence. I didn't catch any fish, but playing around with my flashlight and camera in the rocks proved productive.
In this picture: Mayfly Species Hexagenia limbata (Hex) and Arthropod Order Decapoda (Crayfish).
I lifted a rock in pursuit of a stonefly nymph that had scurried beneath it, and instead I found this Ephemera simulans burrowing mayfly nymph waiting to be photographed.
In this picture: Mayfly Species Ephemera simulans (Brown Drake).
Discussions of Ephemeridae
Hex hatch water temperature range?
4 replies
Posted by NEMatt on May 23, 2014 in the species Hexagenia limbata
Last reply on Jul 5, 2016 by Bombillo
Hi,
New to the site - love it. I was wondering if there was a suggested range of water temperature at which the Hex likes to hatch.
Thanks
Matt
New to the site - love it. I was wondering if there was a suggested range of water temperature at which the Hex likes to hatch.
Thanks
Matt
What is the big DEAL about the HEX?
21 replies
Posted by Spinner on Jun 21, 2006 in the species Hexagenia limbata
Last reply on Jul 5, 2016 by Bombillo
fishing in the dark.......
stepping in holes?
I hate the dark........
I don't need the hex........
Len
stepping in holes?
I hate the dark........
I don't need the hex........
Len
Green Drake Hatch Temp?
1 replies
Posted by NEMatt on May 23, 2014 in the species Ephemera guttulata
Last reply on May 23, 2014 by Entoman
Mayfly larvae -wigglers preservation as bait
20 replies
Posted by Teacherprea on Jun 2, 2007 in the species Hexagenia limbata
Last reply on Apr 29, 2014 by TNEAL
I am a fly fisherman but not a "purist". A friend of mine has a place on the UP of Michigan. He just called me and said a guy told him there is a way to preserve "wigglers." They use them alot up north, those that are not fly fishermen or ladies. They are fishing perch, bluegill and crappie. He heard there is a way to "blanch" them.Drop them in hot water for a few minutes and they turn rubbery. They then will keep indefinitely. Has anyone heard of this? If so, how close to correct is the procedure I mentioned??
Thanks for anyone's help.
Thanks for anyone's help.
GD Shuck
10 replies
Posted by Martinlf on May 29, 2013 in the species Ephemera guttulata
Last reply on Jun 2, 2013 by Crepuscular
Jason's photo of a GD shuck suggests that at hatch time the backs of the nymphs may be a greyish or grey olive color. Possibly useful information, if this is an accurate surmise.
Start a Discussion of Ephemeridae
References
- Arbona, Fred Jr. 1989. Mayflies, the Angler, and the Trout. Nick Lyons Books.
