Lateral view of a Female Hexagenia limbata (Ephemeridae) (Hex) Mayfly Dun from the Namekagon River in Wisconsin

Hex Mayflies
Hexagenia limbata

The famous nocturnal Hex hatch of the Midwest (and a few other lucky locations) stirs to the surface mythically large brown trout that only touch streamers for the rest of the year.

My then-girlfriend, now-wife took this picture with my camera.

From Toughannock Creek in New York

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.

True Bug Family Notonectidae (Backswimmers)

Backswimmers are often important to trout, especially in ponds. They're one of the insects which usually doesn't factor into a fly angler's decisions at all, but it pays to be aware of them because in just-so situations the trout eat nothing else.

Be careful handling them--they have a painful bite.

Where & when

In 954 records from GBIF, adults of this family have mostly been collected during July (22%), August (17%), June (11%), September (10%), October (8%), April (8%), May (6%), and March (6%).

In 52 records from GBIF, this family has been collected at elevations ranging from 23 to 19685 ft, with an average (median) of 2382 ft.

Family Range

source

Map of specific collection sites

Egg-Laying behavior

The adults breathe air. Normally they rest upside down at the water's surface with part of their abdomen sticking up just out of the water to breathe, but they can dive for extended periods carrying an air bubble with them. They are able to leave the water and fly around.

Nymph biology

Diet: Other insects, including other backswimmers

Backswimmer nymphs are fierce predators upon other aquatic insects.

Specimens of Backswimmers:

2 Adults

Notonectidae (Backswimmer) True Bug Adult

4 Pictures

The specimen is right-side-up, but dead, in this picture. The isopropyl alcohol I used to kill it also immediately discolored it.

Dorsal view of a Notonectidae (Backswimmer) True Bug Adult from unknown in Wisconsin

Collected May 17, 2004 from unknown in Wisconsin

Added by Troutnut on January 25, 2006

Collected May 17, 2004 from unknown in Wisconsin and added by Troutnut on January 25, 2006

Notonectidae (Backswimmer) True Bug Adult

1 Picture

Notonectdiae adults can leave the water and fly off whenever they wish. This specimen was caught when it landed on my car. These adults are one of the few aquatic insects that can protect itself with a strong beak.

Collected June 5, 2011 from the Touchet River in Washington

Added by Bnewell on June 26, 2011

Collected June 5, 2011 from the Touchet River in Washington and added by Bnewell on June 26, 2011

Start a Discussion of Notonectidae

References

Schwiebert, Ernest G. 1955. Matching the Hatch. MacMillan Publishing Company.