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Mayfly Species Epeorus pleuralis (Quill Gordon)

Pictures Below
This is the first really good dry-fly opportunity of the season for most Eastern anglers. They are large mayflies and they have good points of vulnerability both underwater and on the surface.  

Where & When

Region: East

Time Of Year (?): April through late May

The Quill Gordon hatch begins in early April in central Appalachian streams and moves into southern Pennsylvania by mid-April. By early May it is going strong in the Catskills, and it lingers through the rest of May in the Adirondacks and New England.

Some books report that this species occurs in the East and the Midwest, though I have not found any accounts of fishable hatches in the Midwest and they are not reported there by the USGS.

Once the pleuralis hatch is triggered by several consecutive days of ideal water temperature, it carries a sort of momentum. The duns supposedly continue to hatch almost every day, regardless of weather, until they are all done.

Hatching Behavior

Time Of Day (?): Early afternoon, usually from 1:00 to 2:00pm; later when hot

Habitat: Riffles and rapids

Water Temperature: 48-53F
Quill Gordon duns crawl out of their nymphal shucks (
Here's an underwater view of the pupal shucks of several already-emerged Brachycentrus numerosus caddisflies.
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.
on the stream bottom and rise to the surface as fully formed adults. This behavior can be well imitated by wet fly imitations. Swisher and Richards describe how to fish the wet in Selective Trout:

It is best fished by casting upstream, allowing it to sink, and then twitching it up through the currents in front of feeding fish.

Once the duns are up, they may ride the surface for a long time and make several failed attempts before getting airborne. Skittering a dry fly accordingly may improve one's success.

Spinner Behavior

Time Of Day: Anytime between noon and dusk, depending on temperature

Habitat: Riffles and rapids
There are several values given in the fly fishing literature for the time it takes Epeorus pleuralis duns to molt and return as spinners. Different books say 1-2 days, 2 days, or 3-4 days.

These spinners can provide good fishing, especially in pocket water in the rapids where they fall spent (Spent: The wing position of many aquatic insects when they fall on the water after mating. The wings of both sides lay flat on the water. The word may be used to describe insects with their wings in that position, as well as the position itself.).

Nymph Biology

Current Speed: Fast

Substrate: Gravel or rock

Environmental Tolerance: Very intolerant of pollution or slow water

Several authors have noted that Epeorus pleuralis nymphs have an unusual habit of gathering en masse on the downstream side of certain objects in the stream prior to emergence. These objects may become a source of unexpected feeding lanes for the trout during emergence.

Epeorus pleuralis Fly Fishing Tips

In the cold water of the early season when the Quill Gordons hatch, the trout may not yet rise freely. Although this hatch can provide good dry fly action, you should not hesitate to fish subsurface.

Pictures of 5 Mayfly Specimens in the Species Epeorus pleuralis:

Specimen Page:12
Male Epeorus pleuralis (Quill Gordon) Mayfly DunMale Epeorus pleuralis (Quill Gordon) Mayfly Dun View 9 PicturesI kept this specimen after photographing it and it molted into a spinner in perfect condition, which I photographed here.
Collected April 30, 2007 from Dresserville Creek in New York
Added to by Troutnut on May 3, 2007
Male Epeorus pleuralis (Quill Gordon) Mayfly SpinnerMale Epeorus pleuralis (Quill Gordon) Mayfly Spinner View 10 PicturesA few days earlier I photographed this same specimen as a dun. The changes between dun and spinner seem particularly dramatic in this species.
Collected April 30, 2007 from Dresserville Creek in New York
Added to by Troutnut on May 3, 2007
Specimen Page:12

2 Streamside Picture of Epeorus pleuralis Mayflies:

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