Blog & Latest Updates
Fly Fishing Articles
Insects by Common Name

Trout Streams & Rivers
Trout Pictures
Underwater Pictures

Desktop Backgrounds
Stream & Bug Videos
Image Use Pricing

Mayfly Family Siphlonuridae (Gray Drakes)

Mayflies

Caddisflies

Stoneflies

Taxonomic Navigation -?-

Kingdom Animalia (Animals)

» Phylum Arthropoda (Arthropods)

» Class Insecta (Insects)

» Order Ephemeroptera (Mayflies)

» Family Siphlonuridae (Gray Drakes)

Genus in Siphlonuridae
SiphlonurusGray Drakes	0	3

3 genera aren't included.

Common Name

Match	Common Name
	Gray Drakes

Pictures Below ↓

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

The behavior and habitat of Siphlonuridae.
3 underwater pictures of Siphlonuridae.

Pictures of 22 Mayfly Specimens in the Family Siphlonuridae:

Specimen Page:1 23

Female Siphlonurus alternatus (Gray Drake) Mayfly Spinner

View 7 PicturesI'm tentatively classifying this one as Siphlonurus alternatus, because it seems to fit that species best in the old keys in Needham's Biology of Mayflies, but I'm hesitant because I can't find documentation that southwest Montana or the surrounding area is within the species' range, although they are widely distributed throughout eastern North American and western Canada.

Collected July 2, 2019 from the Gallatin River in Montana
Added to Troutnut.com by Troutnut on July 18, 2019

Male Siphlonurus occidentalis (Gray Drake) Mayfly Spinner

View 6 Pictures

Collected July 31, 2020 from the Henry's Fork of the Snake River in Idaho
Added to Troutnut.com by Troutnut on August 17, 2020

Female Siphlonurus quebecensis (Gray Drake) Mayfly Spinner

View 4 PicturesThis one had some trouble molting out of the dun stage, but I took pictures anyway.

Collected May 18, 2004 from unknown in Wisconsin
Added to Troutnut.com by Troutnut on January 25, 2006

Female Siphlonurus occidentalis (Gray Drake) Mayfly Spinner

View 9 Pictures

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

Female Siphlonurus occidentalis (Gray Drake) Mayfly Spinner

View 5 PicturesThis specimen was identified by association with this male.

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

Siphlonurus quebecensis (Gray Drake) Mayfly Nymph

View 3 Pictures

Collected May 18, 2004 from unknown in Wisconsin
Added to Troutnut.com by Troutnut on January 25, 2006

Siphlonurus quebecensis (Gray Drake) Mayfly Nymph

View 2 Pictures

Collected June 1, 2005 from the Bois Brule River in Wisconsin
Added to Troutnut.com by Troutnut on May 24, 2006

Male Siphlonurus occidentalis (Gray Drake) Mayfly Spinner

View 6 PicturesThis specimen was easy to key to species using the old keys in < id="115" />, and was the basis for IDs of several other Siphlonurus specimens of the same species collected on the same day.

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

Female Siphlonurus occidentalis (Gray Drake) Mayfly Dun

View 6 PicturesI caught this specimen two days' walk from my macro lenses, but I don't think I have a dun of this species yet, so I took the best photos I could with my iPhone.

Collected August 30, 2020 from Island Lake in Wyoming
Added to Troutnut.com by Troutnut on September 18, 2020

Specimen Page:1 23

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.

Molting: 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.