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.

Stream photos

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Female Hydropsyche (Spotted Sedge) Caddisfly Adult Female Hydropsyche (Spotted Sedge) Caddisfly Adult

Lateral view of a Female Hydropsyche (Hydropsychidae) (Spotted Sedge) Caddisfly Adult from the Columbia River in Washington

7 Recently Added Photos

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.

Stonefly Family Capniidae (Snowflies)

These are the first stoneflies of the year to appear in most parts of the country, and often the first aquatic insects noticed by the angler. Their dark brown or black bodies are easy to spot against the snowbanks where they crawl around.

Capnia in the West and Allocapnia in the East are probably the most common genera of this prolific family.

Where & when

Time of year : Late winter to mid-spring

In 708 records from GBIF, adults of this family have mostly been collected during March (29%), February (24%), January (18%), April (12%), and December (10%).

In 93 records from GBIF, this family has been collected at elevations ranging from 125 to 8648 ft, with an average (median) of 3212 ft.

Family Range

source

Map of specific collection sites

Specimens of the Stonefly Family Capniidae

1 Female Adult

Female Isocapnia hyalita (Little Snowfly) Stonefly Adult

1 Picture

Female Isocapnia hyalita (Capniidae) (Little Snowfly) Stonefly Adult from the Touchet River in Washington

Collected April 20, 2012 from the Touchet River in Washington

Added by Bnewell on April 26, 2012

Collected April 20, 2012 from the Touchet River in Washington and added by Bnewell on April 26, 2012

3 Adults

Capniidae (Snowfly) Stonefly Adult

6 Pictures

Collected March 28, 2006 from Salmon Creek in New York

Added by Troutnut on April 7, 2006

Collected March 28, 2006 from Salmon Creek in New York and added by Troutnut on April 7, 2006

Capniidae (Snowfly) Stonefly Adult

3 Pictures

This drowned Capniidae adult showed up in my drift net sample while I was looking for nymphs. I took photos of the drowned adult in water like a nymph.

Collected March 28, 2006 from Salmon Creek in New York

Added by Troutnut on April 7, 2006

Collected March 28, 2006 from Salmon Creek in New York and added by Troutnut on April 7, 2006

Capnia nana (Little Snowfly) Stonefly Adult

2 Pictures

Capnia nana (Capniidae) (Little Snowfly) Stonefly Adult from the N. Fork Touchet River in Washington

Collected March 6, 2012 from the N. Fork Touchet River in Washington

Added by Bnewell on March 20, 2012

Collected March 6, 2012 from the N. Fork Touchet River in Washington and added by Bnewell on March 20, 2012

6 Nymphs

Capniidae (Snowfly) Stonefly Nymph

4 Pictures

Collected March 12, 2005 from Cascadilla Creek in New York

Added by Troutnut on April 5, 2006

Collected March 12, 2005 from Cascadilla Creek in New York and added by Troutnut on April 5, 2006

Capniidae (Snowfly) Stonefly Nymph

3 Pictures

Collected January 12, 2004 from the Namekagon River in Wisconsin

Added by Troutnut on January 25, 2006

Collected January 12, 2004 from the Namekagon River in Wisconsin and added by Troutnut on January 25, 2006

Capniidae (Snowfly) Stonefly Nymph

3 Pictures

Collected February 6, 2004 from unknown in Wisconsin

Added by Troutnut on January 25, 2006

Collected February 6, 2004 from unknown in Wisconsin and added by Troutnut on January 25, 2006

Utacapnia distincta (Little Snowfly) Stonefly Nymph

1 Picture

Utacapnia distincta (Capniidae) (Little Snowfly) Stonefly Nymph from Teepee Creek in Montana

Upper specimen is a nymph and the lower specimen is a wingless male.

Collected April 14, 2010 from Teepee Creek in Montana

Added by Bnewell on June 26, 2011

Collected April 14, 2010 from Teepee Creek in Montana and added by Bnewell on June 26, 2011

Isocapnia integra (Little Snowfly) Stonefly Nymph

1 Picture

Isocapnia integra (Capniidae) (Little Snowfly) Stonefly Nymph from the Flathead River-upper in Montana

Collected December 18, 2009 from the Flathead River-upper in Montana

Added by Bnewell on June 26, 2011

Collected December 18, 2009 from the Flathead River-upper in Montana and added by Bnewell on June 26, 2011

Utacapnia distincta (Little Snowfly) Stonefly Nymph

1 Picture

Utacapnia distincta (Capniidae) (Little Snowfly) Stonefly Nymph from Crazy Beaver Spring in Montana

Collected January 31, 2007 from Crazy Beaver Spring in Montana

Added by Bnewell on June 26, 2011

Collected January 31, 2007 from Crazy Beaver Spring in Montana and added by Bnewell on June 26, 2011

Discussions of Capniidae

Little Black Stonefly pics

12 replies

Posted by Adirman on Apr 14, 2018 in the species Allocapnia granulata

Last reply on Apr 21, 2018 by Martinlf

Hey guys, went out on the Neversink for awhile today and had a look around, saw a lot of little dark flies, may be the little black stone fly? Hard to tell cuz looked like Caddis too. Looks like about a size 16? Any pics of available of this species would be great.

Thanks

little black stoneflies

5 replies

Posted by CaseyP on Nov 28, 2012

Last reply on Nov 29, 2012 by Entoman

in the winter, we here in the east are told that little black stoneflies might be hatching, so we tie up neat little tiny black things to represent the dries. can anyone steer me to a proper pattern for the nymphs? or is any dark quite small generic nymph going to do the job?

and surely they have a sexy Latin name...

Winter Stones and the like

3 replies

Posted by DarkDun on Nov 20, 2006

Last reply on May 21, 2008 by Greenwolly

I like your site and all it offers. Would like you to come on down to the Southeast and identify our species of mayflies, caddis and plecoptera. Ours are a bit different in makeup than elsewhere and really need cataloging. We constantly are trying to compare our species to the northern hatches and it does not fit into their pattern. We are a month ahead of everywhere else and twice as long in many cases. Some hatches seem to be identifiable and then some defy easy categorization.

DarkDun