When does the Western Hexagenia hatch?

June–July, typically 20:00–dark. It starts from about 16°C, peaks around 19°C and tails off by 24°C.

What flies imitate the Western Hexagenia?

Hexagenia, Hex Cripple, typically on a #6–4 hook.

How big is the Western Hexagenia?

Spinner stage: 27mm. That matches a #6–4 hook.

Mayfly · Aquatic insect

Hexagenia (Western)

Hexagenia limbata

Size

27mm

Hook size

#6–4

Hatch window

Season June–JulyPeak time 20:00–dark

Water temperature

19° peak

16°24°

How fish feed on it

The spent fall comes late, well into the dark, and it is the part that brings the very largest fish up. If you are going to lose sleep for one hatch a year, lose it for this one.

Flies that imitate this

Hexagenia

Hex Cripple

Ecology

Rivers & stillwaterReservoirsTolerates poor water

Where you'll find this

North America — WestPresent
North America — EastPresent

Present throughout

Identification

Hexagenia limbata , the giant mayfly , is a species of mayfly in the family Ephemeridae. It is native to North America where it is distributed widely near lakes and slow-moving rivers. The larvae, known as nymphs, are aquatic and burrow in mud and the adult insects have brief lives.

Mayflies →