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.

Stream photos

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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 Polymitarcyidae (White Fly)

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.

Where & when

In 81 records from GBIF, adults of this family have mostly been collected during July (36%), June (31%), August (16%), May (10%), and September (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

source

Map of specific collection sites

1 Streamside Picture of Polymitarcyidae Mayflies:

View Fullsize

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).

Taken August 14, 2004 from the Couderay River in Wisconsin

Added by Troutnut on January 18, 2006

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 23, 2017 by Crepuscular

What size are these nymphs & Sub Imago's?

Fly choice during an Ephoron hatch

13 replies

Posted by Jmd123 on Aug 3, 2007 in the genus Ephoron

Last reply on Feb 1, 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

Potomac White Fly Hatch - in progress

1 replies

Posted by BrettB on Sep 17, 2008 in the genus Ephoron

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?