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Scientific Name: Hexagenia limbata

Common Names: Hexagenia, hex, big yellow mayfly, giant mayfly


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NYMPH SIZE: 18-35 mm (11/16 to 1-3/8 in)

NYMPH COLOR: yellow-brown

DUN SIZE: 16-35 mm (5/8 to 1-3/8 in)

DUN COLOR: Wing: yellow. Body: yellow or light tan; the underside is solid, but the top can have dark marks on the abdominal segments.

OTHER CHARACTERISTICS: Nymphs have large tusks. Duns have two tails. This is one big bug.


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About Hexagenia Limbata

Among the largest of American mayflies, Hexagenia limbata inhabits some lakes and slow sections of a few rivers. Hatches usually start between May and early July, depending on the local climate; I've seen them hatch in May on the Oregon coast, mid-June in California, and July in the Cascade mountains. The hatch season can last anywhere from three weeks to two months.

Because the nymphs burrow into silty bottoms and only come out to feed at night, it makes no sense to fish a nymph imitation until the hatch season, and even then you need to restrain yourself until near dusk because the hatch doesn't start until the sun kisses the horizon.

An hour or two before the hatch starts, go to water that is less than ten-feet deep. Use a weighted fly or lead on the leader, and let the your nymph settle to the bottom. Pull it up two or three feet, pause, then let it settle back down; repeat this several times before casting again. Sometimes this takes a trout, but mostly it gives you something to do while you're waiting for the actual hatch.

Hatches begin just before sunset, so take a flashlight with you. When you see duns on the surface, forget the nymph and tie on a dry. Cripple imitations can be especially productive during the hatch. Occasionally impart some action to the fly; the naturals can be quite active.

Spinners are not important to anglers.

Articles About Hexagenias

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Quick Tip: The Hex Hatch July is time for Hexagenias, the mayfly the size of a Cadillac. Here's some tips to help you get the most out of the hatch. Scott Richmond


Dun. (photo © 2006 Arlen Thomason. Used by permission.)


Adult. (photo © 2006 Arlen Thomason. Used by permission.)

Matching Hexagenias

Only standard fly patterns are shown. Click here for all matching flies in the database.







Quigley Cripple

8-10/Yellow body and wing

Standard dry fly, Chuck-and-sit

Slow water, lakes


Hexagenia Paradrake

8-10/Yellow body and wing

Standard dry fly, Chuck-and-sit

Slow water, lakes

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