**Mayfly Species Epeorus pleuralis (Quill Gordon)**

Mayflies

Caddisflies

Stoneflies

Taxonomic Navigation -?-

Kingdom Animalia (Animals)

» Phylum Arthropoda (Arthropods)

» Class Insecta (Insects)

» Order Ephemeroptera (Mayflies)

» Family Heptageniidae (March Browns, Cahills, Quill Gordons)

» Genus Epeorus (Little Maryatts)

» Species pleuralis (Quill Gordon)

Common Names

Match	Common Name
	Quill Gordon
	Gordon Quill
	Red Quill Spinner
	Iron Dun
	Blue Quill
	Dark Gordon Quill

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: 48-53°F

Quill Gordon duns crawl out of their nymphal shucks (

View Full Size

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.

5 Mayfly Specimens in the Species Epeorus pleuralis:

Specimen Page:12

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.

Region: Northeast

Collected Apr 30, 2007

Added May 3, 2007

Epeorus pleuralis (Quill Gordon) Mayfly Dun

View 9 Pictures

Region: Catskills

Collected May 7, 2005

Added May 16, 2006

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.

Region: Northeast

Collected Apr 30, 2007

Added May 3, 2007

Specimen Page:12

2 Streamside Pictures of Epeorus pleuralis Mayflies:

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This Epeorus pleuralis nymph tried to hatch into a dun while attached to this rock and apparently got stuck. This species is supposed to emerge from its nymphal shuck (

View Full Size

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 bottom of the stream and swim to the surface as a bedraggled dun. It seems more like this one was trying to crawl out onto a rock to emerge. The rock itself is covered with a thin layer of fast water in a riffle, and apparently it prevented the dun from making any headway. You can see the dun's eyes and a bit of the mesonotum (Mesonotum: The top of the insect mesothorax.) if you look closely.

In this picture: Mayfly Species Epeorus pleuralis (Quill Gordon).

RegionUpper Midwest

Date TakenApr 19, 2006

Date AddedApr 23, 2006

CameraCanon EOS 20D

View Full Size (3.2X larger)

A freshly hatched Quill Gordon dun looks out across the surface of the Catskill stream she just escaped.

In this picture: Mayfly Species Epeorus pleuralis (Quill Gordon).

RegionUpper Midwest

Date TakenMay 7, 2005

Date AddedMar 26, 2006

CameraCanon EOS 20D

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Jargon Defined:

Duns: 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.

Emergence: The transformation of a nymph or pupa into the adult winged stage of an insect. The term may refer to the emergence of an individual, or the daily or yearly event in which all individuals of a species emerge.

Mesonotum: The top of the insect mesothorax.

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.

Nymphs: The juvenile, underwater stages of mayflies, stoneflies, dragonflies, and damselflies and other aquatic insects whose juvenile stages are covered by hard exoskeletons. The word can also refer to the fishing flies which imitate these creatures, in which case it is used as a blanket term for flies imitating any underwater stage of an invertebrate (except for crayfish and leeches).

View Full Size

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.

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.

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.

Useful References:

Arbona, Fred Jr. 1989. Mayflies, the Angler, and the Trout. Nick Lyons Books.

Caucci, Al and Nastasi, Bob. 2004. Hatches II. The Lyons Press.

Fauceglia, Ted. 2005. Mayflies . Stackpole Books.

Knopp, Malcolm and Robert Cormier. 1997. Mayflies: An Angler's Study of Trout Water Ephemeroptera . The Lyons Press.

Schwiebert, Ernest G. 1955. Matching the Hatch. MacMillan Publishing Company.

Swisher, Doug and Carl Richards. 2000. Selective Trout. The Lyons Press.