Western Ameletid Mayfly vs Cahill Mayfly

Side-by-side species comparison

Attribute Western Ameletid Mayfly Cahill Mayfly
Scientific Name Ameletus cooki Stenacron interpunctatum
Order Ephemeroptera Ephemeroptera
Family Ameletidae Heptageniidae
Size 8-12 mm 8-12 mm
Habitat Mountains Rivers & Streams
Diet Omnivores Detritivores
Regions North America North America
Conservation Least Concern Least Concern

Western Ameletid Mayfly

A streamlined mayfly found in cold mountain streams of the Pacific Northwest. Nymphs are agile swimmers that dart between cobbles in riffles.

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Did You Know?

Nymphs are strong enough swimmers to move upstream against moderate currents.

Cahill Mayfly

A cream-to-tan colored mayfly found throughout eastern North America. It is named after the classic Light Cahill fly fishing pattern it inspired.

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Did You Know?

The Light Cahill fly pattern, inspired by this mayfly, has been a staple of American fly fishing since the 1880s.