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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 2 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:123 4...28

Drunella doddsii (Western Green Drake) Mayfly Nymph

View 12 Pictures

Collected July 17, 2011 from the Gulkana River in Alaska
Added to Troutnut.com by Troutnut on July 20, 2011

Male Ephemerella subvaria (Hendrickson) Mayfly Dun

View 9 PicturesI collected this male Hendrickson dun and a female in the pool on the Beaverkill where the popular Hendrickson pattern was first created. He is descended from mayfly royalty.

Collected April 19, 2006 from the Beaverkill River in New York
Added to Troutnut.com by Troutnut on April 22, 2006

Female Attenella margarita (Little Western Blue-Winged Olive) Mayfly Dun

View 6 PicturesI found this dun unusually late in the year for anything in the Ephemerellidae family in the East. It's also small for that family.

Collected September 4, 2006 from Willowemoc Creek in New York
Added to Troutnut.com by Troutnut on October 3, 2006

Male Drunella spinifera (Western Slate Olive Dun) Western Slate Olive Dun Nymph

Male Drunella spinifera (Western Slate Olive Dun) Mayfly Nymph

View 8 PicturesIn a bucket full of Drunella coloradensis nymphs, this was the only specimen of Drunella spinifera (and the first one I've found anywhere).

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

Female Ephemerella excrucians (Pale Morning Dun) Mayfly Spinner

View 11 Pictures

Collected July 1, 2005 from the Bois Brule River in Wisconsin
Added to Troutnut.com by Troutnut on April 22, 2006

Penelomax septentrionalis Mayfly Nymph

View 12 PicturesThis is surely the most distinctive-looking species in Ephemerellidae. I like the rugged, spindly look. If mayflies made movies, Penelomax septentrionalis would probably play the supervillain.

Maybe I should take a break and get something to eat.

Collected May 13, 2007 from the Delaware River in New York
Added to Troutnut.com by Troutnut on May 18, 2007

Male Ephemerella subvaria (Hendrickson) Mayfly Spinner

View 11 PicturesI collected this beautiful male Hendrickson specimen as a dun, along with a female Hendrickson from the same hatch. Both molted into spinners in my house within a couple of days.

Collected April 23, 2007 from Fall Creek in New York
Added to Troutnut.com by Troutnut on April 25, 2007

Female Drunella tuberculata Mayfly Dun

View 14 PicturesI don't know for sure that this is Drunella tuberculata, but that's my best guess for now.

It certainly has a different look and much more robust body shape from Drunella lata duns I photographed a couple weeks earlier, so I doubt it's that species. Using distribution records to eliminate other choices narrows this down to Drunella tuberculata or Drunella walkeri.

Markings described for the abdominal sternites (

One sternite of this Isonychia bicolor mayfly spinner is highlighted in red.

Sternite: The bottom (ventral) part of a single segment on an insect's abdomen.) of the male spinner of Drunella tuberculata are suspiciously similar to those on this female dun. Also, this dun is 9.5mm long (my ruler pic isn't very good, but I'm basing this on measuring the real thing). The size range given in the old Allen & Edmunds keys for walkeri females is 7-8mm, while tuberculata is 9-11mm. For these reasons I'm sticking it in tuberculata for now.

This is the only Drunella mayfly I saw all day. I scooped it off the water as it emerged at around 7pm from a big Catskill tailwater.

Collected June 1, 2007 from the West Branch of the Delaware River in New York
Added to Troutnut.com by Troutnut on June 8, 2007

Ephemerella subvaria (Hendrickson) Mayfly Nymph

View 7 PicturesThis is another unusual brown Ephemerella nymph. The "fan-tail" which defines the Ephemerella genus is particularly evident on this specimen.

Collected February 7, 2004 from unknown in Wisconsin
Added to Troutnut.com by Troutnut on January 25, 2006

Female Ephemerella subvaria (Hendrickson) Mayfly Dun

View 9 PicturesI 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.

Collected April 19, 2006 from the Beaverkill River in New York
Added to Troutnut.com by Troutnut on April 22, 2006

Specimen Page:123 4...28

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.

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).

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.

One sternite of this Isonychia bicolor mayfly spinner is highlighted in red.

Sternites: The bottom (ventral) part of a single segment on an insect's abdomen.

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.