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Mayfly Genus Ephemerella (Hendricksons, Sulphurs, PMDs)

Taxonomic Navigation -?-
» Genus Ephemerella (Hendricksons, Sulphurs, PMDs)
Species in EphemerellaNumber of SpecimensNumber of Pictures
Ephemerella aurivillii18109
Ephemerella dorothea dorotheaPale Evening Dun211
Ephemerella dorothea infrequensPale Morning Dun48
Ephemerella excruciansPale Morning Dun15
Ephemerella invariaSulphur Dun46190
Ephemerella needhamiLittle Dark Hendrickson941
Ephemerella subvariaHendrickson34162
Ephemerella tibialisSmall Western Dark Hendrickson11

11 species aren't included.
Common Name
MatchCommon Name
****Hendricksons, Sulphurs, PMDs
Pictures Below ↓

This is page 3 of specimens of Ephemerella. Visit the main Ephemerella page for:

  • The behavior and habitat of Ephemerella.
  • 37 underwater pictures of Ephemerella.
  • 6 streamside pictures of Ephemerella.

Pictures of 128 Mayfly Specimens in the Genus Ephemerella:

Specimen Page:1234...14
Female Ephemerella invaria (Sulphur Dun) Mayfly DunFemale Ephemerella invaria (Sulphur Dun) Mayfly Dun View 6 Pictures
Collected May 28, 2005 from the Teal River in Wisconsin
Added to Troutnut.com by Troutnut on May 24, 2006
Male Ephemerella invaria (Sulphur Dun) Mayfly DunMale Ephemerella invaria (Sulphur Dun) Mayfly Dun View 7 Pictures
Collected May 26, 2007 from Penn's Creek in Pennsylvania
Added to Troutnut.com by Troutnut on June 4, 2007
Ephemerella subvaria (Hendrickson) Mayfly NymphEphemerella subvaria (Hendrickson) Mayfly Nymph View 3 PicturesThis is one of the nymphs I collected doing something very, very strange on March 17th 2004. In the middle of the day, around 2 pm, in the water right around my feet I watched lots of Ephemerella nymphs clumsily swimming up all the way to the surface and then just kind of drifting and wiggling around in the water column. None hatched. They seemed to do it more intensely when the sun was out. It wasn't the time of day for the normal invertebrate drift phenomenon, and as far as I know invertebrate drift doesn't involve this kind of clear effort to swim all the way to the surface. I didn't need a net to catch them, I just reached down into the water and grabbed them with my fingers just below the surface.

The prominent abdominal tubercles (
A few (not all) of the abdominal tubercles on this Ephemerella needhami nymph are circled. They are especially large in this species.
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.) aren't quite black, though, and the general color is a dark brown, though I saw nymphs with all Hendrickson color stages behaving strangely.
Collected March 17, 2004 from the Namekagon River in Wisconsin
Added to Troutnut.com by Troutnut on January 25, 2006
Male Ephemerella aurivillii Mayfly DunMale Ephemerella aurivillii Mayfly Dun View 9 PicturesThis dun hatched in my aquarium on July 16th from an easily identified nymph collected on July 10th, and it molted into a spinner after I photographed it. The beautiful spinner form is listed as separate specimen. I forgot to photograph the dun with the ruler, but naturally his size is pretty similar to what it was as a spinner.
Collected July 10, 2011 from Nome Creek in Alaska
Added to Troutnut.com by Troutnut on July 16, 2011
Ephemerella aurivillii Mayfly NymphEphemerella aurivillii Mayfly Nymph View 5 PicturesClose examination under a microscope showed definite small tubercles (
A few (not all) of the abdominal tubercles on this Ephemerella needhami nymph are circled. They are especially large in this species.
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.) on the back of this nymph.
Collected February 5, 2004 from unknown in Wisconsin
Added to Troutnut.com by Troutnut on January 25, 2006
Ephemerella aurivillii Mayfly NymphEphemerella aurivillii Mayfly Nymph View 7 Pictures
Collected May 10, 2008 from the Chena River in Alaska
Added to Troutnut.com by Troutnut on April 20, 2011
Male Ephemerella aurivillii Mayfly DunMale Ephemerella aurivillii Mayfly Dun View 14 PicturesThis is the most widespread species of Ephemerella, and also the most abundant in some places, but nobody I've talked to seemed to know what its duns looked like, and there were no pictures of its duns online or in any angling books. That mystery is solved with this male dun, which hatched from a definitively identified nymph.
Collected July 10, 2011 from Nome Creek in Alaska
Added to Troutnut.com by Troutnut on July 12, 2011
Ephemerella aurivillii Mayfly NymphEphemerella aurivillii Mayfly Nymph View 9 PicturesI'm pretty sure this is Ephemerella aurivillii. The body is 11mm long, which rules out most other species, and the hind legs seem to be more than 1.5 times longer than the fore legs -- a key characteristic for this species.

This specimen isn't in the best of shape, as it's missing all three tails, but it's the only one of its species I captured in this sample.
Collected May 6, 2007 from Mongaup Creek in New York
Added to Troutnut.com by Troutnut on May 18, 2007
Male Ephemerella subvaria (Hendrickson) Mayfly DunMale Ephemerella subvaria (Hendrickson) Mayfly Dun View 5 Pictures
Collected May 1, 2004 from the Namekagon River in Wisconsin
Added to Troutnut.com by Troutnut on January 25, 2006
Ephemerella needhami (Little Dark Hendrickson) Mayfly NymphEphemerella needhami (Little Dark Hendrickson) Mayfly Nymph View 5 PicturesI took quite a few notes at the microscope when I collected this specimen. They're attached to the appropriate pictures.

I found this specimen in the same collection as a similar one. Since I only have strange views of this one, it's possible that they're actually the same specimen and I somehow confused my picture-ordering and got the impression that they're different nymphs.
Collected June 8, 2005 from the Namekagon River in Wisconsin
Added to Troutnut.com by Troutnut on May 26, 2006
Specimen Page:1234...14
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