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Lateral view of a Male Baetis (Baetidae) (Blue-Winged Olive) Mayfly Dun from Mystery Creek #43 in New York
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.

Dorsal view of a Skwala (Perlodidae) (Large Springfly) Stonefly Nymph from the Yakima River in Washington
This Skwala nymph still has a couple months left to go before hatching, but it's still a good representative of its species, which was extremely abundant in my sample for a stonefly of this size. It's obvious why the Yakima is known for its Skwala hatch.
27" brown trout, my largest ever. It was the sub-dominant fish in its pool. After this, I hooked the bigger one, but I couldn't land it.
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.

Red Quills

Like most common names,"Red Quill" can refer to more than one taxon. They're previewed below, along with 12 specimens. For more detail click through to the scientific names.

Mayfly Species Ephemerella subvaria

These are often called Red Quills.
The Hendrickson hatch is almost synonymous with fly fishing in America. It has been romanticized by our finest writers, enshrined on an untouchable pedestal next to Theodore Gordon, bamboo, and the Beaverkill.

The fame is well-deserved. Ephemerella subvaria is a prolific species which drives trout to gorge themselves. Its subtleties demand the best of us as anglers, and meeting the challenge pays off handsomely in bent graphite and screaming reels.
Lateral view of a Female Ephemerella subvaria (Ephemerellidae) (Hendrickson) Mayfly Dun from the Beaverkill River in New York
I collected this female Hendrickson dun and a male in the pool on the Beaverkill where the popular Hendrickson pattern was first created. She is descended from mayfly royalty.
Ruler view of a Female Ephemerella subvaria (Ephemerellidae) (Hendrickson) Mayfly Spinner from the Bois Brule River in Wisconsin The smallest ruler marks are 1/16".
This one's a bit bedraggled because it was rainy and I had a hard time keeping anything dry, including the container I was putting mayflies in. I was practically juggling up there balanced on a rock trying to catch mayflies and trout at the same time.
Ephemerella subvaria (Ephemerellidae) (Hendrickson) Mayfly Nymph from unknown in Wisconsin
This is another unusual brown Ephemerella nymph. The "fan-tail" which defines the Ephemerella genus is particularly evident on this specimen.

Mayfly Species Ephemerella invaria

These are sometimes called Red Quills.
This species, the primary "Sulphur" hatch, stirs many feelings in the angler. There is nostalgia for days when everything clicked and large, selective trout were brought to hand. There is the bewildering memory of towering clouds of spinners which promise great fishing and then vanish back into the aspens as night falls. There is frustration from the maddening selectivity with which trout approach the emerging duns--a vexing challenge that, for some of us, is the source of our excitement when Sulphur time rolls around.

Ephemerella invaria is one of the two species frequently known as Sulphurs (the other is Ephemerella dorothea). There used to be a third, Ephemerella rotunda, but entomologists recently discovered that invaria and rotunda are a single species with an incredible range of individual variation. This variation and the similarity to the also variable dorothea make telling them apart exceptionally tricky.

As the combination of two already prolific species, this has become the most abundant of all mayfly species in Eastern and Midwestern trout streams.
Lateral view of a Male Ephemerella invaria (Ephemerellidae) (Sulphur) Mayfly Dun from Penn's Creek in Pennsylvania
Lateral view of a Male Ephemerella invaria (Ephemerellidae) (Sulphur) Mayfly Spinner from the Teal River in Wisconsin
Dorsal view of a Ephemerella invaria (Ephemerellidae) (Sulphur) Mayfly Nymph from the Beaverkill River in New York
This small Ephemerella invaria nymph was at least a month away from emergence.

Mayfly Species Neoleptophlebia adoptiva

These are very rarely called Red Quills.
This is the best Spring hatch after the Quill Gordons (Epeorus pleuralis) but before the Hendricksons (Ephemerella subvaria) in most parts of the East, although it can overlap with both. The Blue Quills are small mayflies (hook size 16-20) but they can hatch in incredible numbers at a time when eager trout are just beginning to look to the surface after a hungry winter.
Lateral view of a Male Neoleptophlebia adoptiva (Leptophlebiidae) (Blue Quill) Mayfly Spinner from Factory Brook in New York
Based on the pale longitudinal forewing veins (excepting the costals), dark middle terga, and genitalia (Burks '53), this specimen is P. adoptiva.

Mayfly Species Rhithrogena impersonata

These are very rarely called Red Quills.
This intriguing species has two distinct colors of nymphs, which were once considered to be different species. Most nymphs are a dark olive gray, but some are a surprisingly bright reddish brown. The red ones were once classified as Rhithrogena sanguinea. There is no apparent difference between the adults of the two varieties.
Dorsal view of a Rhithrogena impersonata (Heptageniidae) (Dark Red Quill) Mayfly Nymph from Mongaup Creek in New York
This was the only Rhithrogena specimen in a large sample of nymphs from a small Catskill stream. It looks virtually identical to Rhithrogena impersonata specimens collected in the Midwest, but I didn't get to check the distinguishing features under a microscope.

Mayfly Species Rhithrogena jejuna

These are very rarely called Red Quills.

Mayfly Species Ephemerella tibialis

These are very rarely called Red Quills.
Ehhemerella tibialis (Little Western Red Quill, Little Western Dark Hendrickson) is a common western species that can be very important at times. It is perhaps also one of the most confusing species. Unlike it's western generic counterparts the species is described as dark and their females produce dark eggs. Until recently, it was classified in the Serratella genus with species that share these traits. Regardless, it is the only small, dark ephemerellid the western angler is likely to find important. Favorite patterns used for size 18 Pale Morning Dun hatches tied in eastern Dark Hendrickson colors should be the ticket.

As with many of it's sister species it is widely adaptable and may be variable in its appearance. Scientific literature and many angling sources describe it as a small dark mayfly. Not everybody agrees. Ralph Cutter, West Coast author of several angler/entomology books and articles describes it in Sierra Trout Guide as a much larger pale mayfly and dubs it the Creamy Orange Dun. He also mentions the nymph as being easy to recognize by the faint dorsal stripe running down its back and its often fiery brownish red color. These descriptions also match a variation of the ubiquitous and common Ephemerella excrucians.

Mayfly Species Rhithrogena undulata

These are very rarely called Red Quills.
This is one of the two most common species of Rhithrogena.
Male Rhithrogena undulata (Heptageniidae) (Small Western Red Quill) Mayfly Spinner from the Madison River in Montana
This male was collected at the same time as this female and is likely the same species.

It keys pretty clearly to Rhithrogena undulata using the key in Traver 1935, although the size is larger than expected for that species in that source.
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