Mayfly Family Polymitarcyidae (White Flies)

Mayflies

Caddisflies

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Taxonomic Navigation -?-

Kingdom Animalia (Animals)

» Phylum Arthropoda (Arthropods)

» Class Insecta (Insects)

» Order Ephemeroptera (Mayflies)

» Family Polymitarcyidae (White Flies)

Genus in Polymitarcyidae
EphoronWhite Flies	0	1

2 genera aren't included.

Common Name

Match	Common Name
	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.

1 Streamside Picture of Polymitarcyidae Mayflies:

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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 (

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Here's an underwater view of the pupal shucks of several already-emerged Brachycentrus numerosus caddisflies.

Shuck: The shed exoskeleton left over when an insect molts into its next stage or instar. Most often it describes the last nymphal or pupal skin exited during emergence into a winged adult.) 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 Flies).

RegionUpper Midwest

Date TakenAug 14, 2004

Date AddedJan 18, 2006

CameraOlympus C740UZ

Recent Discussions of Polymitarcyidae

Potomac White Fly Hatch - in progress 1 Reply »

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.

Reply Fly choice during an Ephoron hatch 11 Replies »

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

Last reply on Sep 25, 2007 by Gene

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

Reply Ephoron Leukon nymph photographs 12 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?

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Jargon Defined:

Dun: Mayflies have two adult stages. They first emerge from the water as duns (scientifically known as the subimago stage). They then molt into the spinner (imago) stage, in which they mate and die. Sometimes the word "dun" is confusingly used to refer to a brownish gray color in fly tying materials.

Molt: When aquatic insects with hard exoskeletons (like mayfly and stonefly nymphs) grow bigger, their exoskeleton does not grow with them. Instead they grow a new, larger one underneath and shed the old one when it's too small. This process is called molting.

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Here's an underwater view of the pupal shucks of several already-emerged Brachycentrus numerosus caddisflies.

Shucks: The shed exoskeleton left over when an insect molts into its next stage or instar. Most often it describes the last nymphal or pupal skin exited during emergence into a winged adult.

Spinner: There are two winged stages of adult mayflies. They emerge from the water as duns, molt on land (usually) into their fully mature stage, spinners. As spinners, they mate, lay eggs, and die.