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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.

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Mayfly Species Eurylophella temporalis (Chocolate Dun)

Where & when

Time of year : Mid-May through mid-late June

Preferred waters: Lakes and large streams

This widespread Eastern and Midwestern species is not really mentioned in fly fishing literature. The Leonards say in Mayflies of Michigan Trout Streams that it is found in lakes and small streams. Some ready-to-emerge nymphs I collected in northern Wisconsin came from the very small headwaters of a small stream in early June, while other adults were found emerging in long, broad, lake-like flats of a warmwater smallmouth stream on June 21st.
Species Range

Hatching behavior

The only emergence I've witnessed was midday on a lake-like flat on a warmwater stream. Nymphs appeared to be emerging through the surface film throughout the river, possibly more concentrated near shore.

Specimens of the Mayfly Species Eurylophella temporalis

1 Male Dun
1 Female Dun
1 Male Spinner
1 Female Spinner
1 Nymph

Discussions of Eurylophella temporalis

florida mayfly nymph imitations
2 replies
Posted by Homer47 on Sep 5, 2012
Last reply on Sep 6, 2012 by Sayfu
Looks like an imitation would be about a #10 or #8 dark brown nymph pattern. I'm down here in north Fla and trying to match the hatch in the far north central part of the state, mostly to fool the bream. Any ideas or help would be appreciated. I found two patterns so far that seem to work- a little brown nymph with a rusty brown/orange thorax(maybe this is a good representation of the E. Temporalis), and a size 12 buzzer nymph with black body, peacock thorax and white breathing filament. The bream seemed to agree with that choice. I would like to try and copy more local insects as I figure out what they are.There are dragonflies and damselflies and mosquitoes. I could start there.

Start a Discussion of Eurylophella temporalis


  • Allen, R.K., and Edmunds, George F. Jr. 1963. A Revision of the Genus Ephemerella (Ephemeroptera: Ephemerellidae) VII. The Subgenus Eurylophella. Canadian Entomologist 95: 597-623.
  • Leonard, Justin W. and Fannie A. Leonard. 1962. Mayflies of Michigan Trout Streams. Cranbrook Institute of Science.

Mayfly Species Eurylophella temporalis (Chocolate Dun)

Species Range
Common Name
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