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Mayfly Family Ephemerellidae (Hendricksons, Sulphurs, PMDs, BWOs)

Mayflies

Caddisflies

Stoneflies

Taxonomic Navigation -?-

Kingdom Animalia (Animals)

» Phylum Arthropoda (Arthropods)

» Class Insecta (Insects)

» Order Ephemeroptera (Mayflies)

» Family Ephemerellidae (Hendricksons, Sulphurs, PMDs, BWOs)

Genus in Ephemerellidae
Attenella	0	0
Caudatella	0	0
Dannella	0	0
DrunellaBlue-Winged Olives	0	0
EphemerellaHendricksons, Sulphurs, PMDs	0	37
EurylophellaChocolate Duns	0	0
Matriella	0	0
Penelomax	0	0
Serratella	0	0
TeloganopsisLittle black Quills	0	0
Timpanoga	0	0

3 genera aren't included.

Common Name

Match	Common Name
	Hendricksons, Sulphurs, PMDs, BWOs

Pictures Below ↓

This is page 27 of specimens of Ephemerellidae. Visit the main Ephemerellidae page for:

The behavior and habitat of Ephemerellidae.
37 underwater pictures of Ephemerellidae.

Pictures of 271 Mayfly Specimens in the Family Ephemerellidae:

Specimen Page:1...25 262728

Ephemerella invaria (Sulphur Dun) Mayfly Nymph

View 3 PicturesI confirmed with the microscope that this nymph has small tubercles (

A few (not all) of the abdominal tubercles on this Ephemerella needhami nymph are circled. They are especially large in this species.

Tubercle: Various peculiar little bumps or projections on an insect. Their character is important for the identification of many kinds of insects, such as the nymphs of Ephemerellidae mayflies.), single-banded tibiae (

The tibia of this Isonychia bicolor mayfly spinner is highlighted in red.

Tibia: A middle segments in the leg of an insect, located between the femur and the tarsus.), and a fan tail.

Collected March 10, 2004 from unknown in Wisconsin
Added to Troutnut.com by Troutnut on January 25, 2006

Female Drunella flavilinea (Flav) Mayfly Dun

View 6 PicturesI can't be certain of the ID of this female dun, but I'm calling it Drunella flavilinea for three reasons: 1) the known abundance of "flavs" on the Henry's Fork, 2) clear differences in coloration from my confirmed specimens of Drunella coloradensis, which is the main lookalike, and 3) the habitat (a sizable river in a wide mountain valley, rather than a small, high-altitude stream) suggests it's not coloradensis.

Collected July 31, 2020 from the Henry's Fork of the Snake River in Idaho
Added to Troutnut.com by Troutnut on August 16, 2020

Drunella grandis (Western Green Drake) Mayfly Nymph

View 2 Pictures

Collected June 16, 2005 from the Vermillion River in Montana
Added to Troutnut.com by Bnewell on June 27, 2011

Drunella coloradensis (Small Western Green Drake) Mayfly Nymph

View 5 Pictures

Collected July 28, 2019 from Mystery Creek #199 in Washington
Added to Troutnut.com by Troutnut on July 30, 2019

Ephemerella (Hendricksons, Sulphurs, PMDs) Mayfly Nymph

View 2 PicturesI only took two partial pictures of this specimen to test out one of my microscopes.

Collected November 15, 2004 from Fall Creek in New York
Added to Troutnut.com by Troutnut on April 12, 2006

Drunella coloradensis (Small Western Green Drake) Mayfly Nymph

View 4 PicturesThis one nicely illustrates the variation in coloration within an single Ephemerellid species in a single stream, when compared to its darker, more uniform counterpart.

Collected July 25, 2019 from Mystery Creek #249 in Washington
Added to Troutnut.com by Troutnut on July 26, 2019

Ephemerella excrucians (Pale Morning Dun) Mayfly Nymph

View 2 PicturesThis mature nymph is associated with the dun from the same location and date posted on this hatch page. Size 10mm.

Collected November 12, 2011 from the Fall River in California
Added to Troutnut.com by Entoman on December 15, 2011

Female Ephemerellidae (Hendricksons, Sulphurs, PMDs, BWOs) Mayfly Dun

View 4 Pictures

Collected August 11, 2018 from the Henry's Fork of the Snake River in Idaho
Added to Troutnut.com by Troutnut on June 12, 2019

Drunella doddsii (Western Green Drake) Mayfly Nymph

View 1 PicturesThis is a photo of the ventral (Ventral: Toward or on the bottom.) surface of this nymph which acts to help hold the nymph on rock surfaces.

Collected July 5, 2007 from Many streams in Montana
Added to Troutnut.com by Bnewell on June 26, 2011

Male Ephemerellidae (Hendricksons, Sulphurs, PMDs, BWOs) Mayfly Dun

View 4 Pictures

Collected August 11, 2018 from the Henry's Fork of the Snake River in Idaho
Added to Troutnut.com by Troutnut on June 12, 2019

Specimen Page:1...25 262728

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.

Nymph: 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).

The tibia of this Isonychia bicolor mayfly spinner is highlighted in red.

Tibiae: A middle segments in the leg of an insect, located between the femur and the tarsus.

A few (not all) of the abdominal tubercles on this Ephemerella needhami nymph are circled. They are especially large in this species.

Tubercles: Various peculiar little bumps or projections on an insect. Their character is important for the identification of many kinds of insects, such as the nymphs of Ephemerellidae mayflies.

Ventral: Toward or on the bottom.

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.

Leonard, Justin W. and Fannie A. Leonard. 1962. Mayflies of Michigan Trout Streams. Cranbrook Institute of Science.