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 Family Polymitarcyidae (White Flies)
This is the only family of burrowing mayflies, besides Ephemeridae, which is abundant in the United States. All the trout fly fishing action comes from the genus Ephoron, because the other two genera reside in warm waters in the South.
Read about Ephoron for more details.
Read about Ephoron for more details.
Where & when
In 81 records from GBIF, adults of this family have mostly been collected during August (36%), July (31%), September (16%), June (10%), and October (6%).
In 38 records from GBIF, this family has been collected at elevations ranging from 618 to 6250 ft, with an average (median) of 3691 ft.
Family Range
Identification
To determine whether a specimen of Ephemeroptera belongs to Polymitarcyidae, use the Key to Families of Mayfly Nymphs or Key to Families of Mayfly Duns and Spinners.
1 Streamside Picture of Polymitarcyidae Mayflies:
This nighttime flash photograph shows a bunch of Ephoron mayflies flying around during the hatch. So many of them fly around with their dun shucks attached that it seems like they molt from the dun to spinner stage in mid-air. Actually they molt on streamside vegetation like other mayflies, but they sometimes take off to mate before they're completely finished.
In this picture: Mayfly Genus Ephoron (White Fly).
Discussions of Polymitarcyidae
Yea...
Posted by Imaxfli on Oct 23, 2020 in the species Ephoron leukon
Last reply on Oct 23, 2020 by Imaxfli
Me too looking for photos or better yet, video of matching. These things seem to pop outa the water like no other ......
Polymitarcyidae Question
1 replies
Posted by Steamntrout on Jun 22, 2017 in the species Ephoron album
Last reply on Jun 22, 2017 by Crepuscular
What size are these nymphs & Sub Imago's?
Fly choice during an Ephoron hatch
13 replies
Last reply on Jan 31, 2016 by Martinlf
Hey folks, what would you recommend as an imitation of these guys? They're hatching furiously in the Huron River in/near Ann Arbor, MI (smallmouth are leaping out of the water to eat them). How about a Light Cahill or White Wulff? Both have been major producers for me on other streams with white mayfly hatches in summer (e.g., Rifle River). If anyone has a particular recipe that works for them, I'd like to know. Thanks!
Jonathon
Jonathon
Potomac White Fly Hatch - in progress
1 replies
Last reply on Sep 21, 2008 by GONZO
There's quite a big white fly hatch on the Potomac at least around Harper's Ferry. Does anyone know a good nymph or emerger pattern for the white fly hatch? I plan to hit it early, prior to duns coming off and know there is a good deal of nymphal movement and drift beforehand. Maybe I'll collect a few tonight to see color / size / behavior. Any thoughts are appreciated.
Ephoron Leukon nymph photographs
11 replies
Posted by BFornadley on Feb 8, 2007 in the species Ephoron leukon
Last reply on Aug 14, 2007 by Gene
I need some help here. I have been looking all over the web for someone who may have taken some Ephoron Leukon nymph underwater (or out of water) photos.I saw the description here at "Troutnut.com" and advice that a smaller Brown Drake (Ephemera) nymph would be a good natural to use as a tying model but I really want to see the real thing. Does any body have any of these pics or can anyone definitively tell me where to look?
Start a Discussion of Polymitarcyidae
References
- 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 Family Polymitarcyidae (White Flies)
Taxonomy
2 genera (Tortopsis and Tortopus) aren't included.