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.
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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.
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Mayfly Genus Ephemera
This genus of large mayflies boasts three species of great importance. Ephemera simulans and Ephemera guttulata, the Brown Drakes and Green Drakes, are both legendary for short-lived periods of blizzard-like hatches. The Yellow Drakes, Ephemera varia, have a slow and steady emergence period, providing consistent low-key action for several midsummer weeks.
Ephemera blanda is a very localized species and unimportant to most anglers. Ephemera compar, sometimes mentioned in older books as a minor Western hatch, is now considered to be extinct.
Several important characteristics vary between the three important species. Read about each one for details.
Ephemera blanda is a very localized species and unimportant to most anglers. Ephemera compar, sometimes mentioned in older books as a minor Western hatch, is now considered to be extinct.
Several important characteristics vary between the three important species. Read about each one for details.
Genus Range
Nymph biology
Most Ephemera species burrow into rougher substrate than Hexagenia nymphs do. They inhabit sand and fine gravel more frequently than firm silt, although they are found in those environments too.Specimens of the Mayfly Genus Ephemera
1 Male Dun
2 Female Duns
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.
3 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.
This one hatched in the middle of July, which is very late for this species.
2 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.
13 Nymphs
Here's an unusually small early instar nymph.
3 Streamside Pictures of Ephemera 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).
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).
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).
2 Underwater Pictures of Ephemera Mayflies:
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 Ephemera
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
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.
Brown Drake?
20 replies
Posted by Derdmann on Jun 19, 2011 in the species Ephemera simulans
Last reply on Jun 29, 2011 by TNEAL
Came across a mayfly on the Paint River by Crystal Falls, Michigan on June 17th. Is it a brown drake?
Thanks.
Thanks.
Emergence period of green drakes
5 replies
Posted by Beardius on Aug 1, 2008 in the species Ephemera guttulata
Last reply on Dec 4, 2008 by Beardius
Emergence periods for green drakes usually run for 7-10 days in most streams. However, there are streams in the east where emergence periods are prolonged by some of the nymphs being parasitized by Nanocladius and Epoicocladius midge larvae. In these streams, emergence may be prolonged to 21 days. Unparasitized nymphs emerge before parasitized nymphs, with each group showing separate peaks of emergence about a week apart. This is based upon my own research on green drake emergence in streams with these midge species.
My question here is this: does anybody know of streams that have this type of prolonged emergence (2-3 weeks) in NY, PA, MD, or WV?
My question here is this: does anybody know of streams that have this type of prolonged emergence (2-3 weeks) in NY, PA, MD, or WV?
Green Drake Hatch Frustrations
7 replies
Posted by Billy on Jun 6, 2007 in the species Ephemera guttulata
Last reply on Jun 12, 2007 by GONZO
We were fortunate this past weekend to be on Pine Creek during the Green Drake hatch. The spinner fall was incredible. A question I have is why do we miss so many strikes and yet, using the same techniques, the ones we do catch and release practically hook themselves. We were getting strikes on Green Drake Duns and Cripples and Spinners.
One individual described it to us that after observing the trout underwater during a Green Drake hatch, many of the strikes pull a small part of the fly (wing, leg) underwater and they swirl and swallow it there. If that is true, then I can rationalize missing more than 18 fish this weekend. If anyone has observed this please post your observations. Normally we do not have such a great contrast in miss to hookup ratio.
One individual described it to us that after observing the trout underwater during a Green Drake hatch, many of the strikes pull a small part of the fly (wing, leg) underwater and they swirl and swallow it there. If that is true, then I can rationalize missing more than 18 fish this weekend. If anyone has observed this please post your observations. Normally we do not have such a great contrast in miss to hookup ratio.
Start a Discussion of Ephemera
References
- Arbona, Fred Jr. 1989. Mayflies, the Angler, and the Trout. Nick Lyons Books.
- Jacobus, L. M., Wiersema, N.A., and Webb, J.M. 2014. Identification of Far Northern and Western North American Mayfly Larvae (Insecta: Ephemeroptera), North of Mexico; Version 2. Joint Aquatic Science meeting, Portland, OR. Unpublished workshop manual. 1-176.
- Merritt R.W., Cummins, K.W., and Berg, M.B. 2019. An Introduction to the Aquatic Insects of North America (Fifth Edition). Kendall/Hunt Publishing Company.
Mayfly Genus Ephemera
Taxonomy
Species in Ephemera
Ephemera blanda
0
0
Ephemera guttulataGreen Drakes
3
36
Ephemera simulansBrown Drakes
15
81
Ephemera variaYellow Drakes
3
17
1 species (Ephemera traverae) isn't included.