Sulphur Mayfly vs Cahill Mayfly

Side-by-side species comparison

Attribute Sulphur Mayfly Cahill Mayfly
Scientific Name Ephemerella dorothea Stenacron interpunctatum
Order Ephemeroptera Ephemeroptera
Family Ephemerellidae Heptageniidae
Size 6-9 mm 8-12 mm
Habitat Rivers & Streams Rivers & Streams
Diet Omnivores Detritivores
Regions North America North America
Conservation Least Concern Least Concern

Sulphur Mayfly

A small pale yellow mayfly that produces reliable evening hatches on eastern North American streams. One of the most important species for fly anglers.

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Did You Know?

Sulphur mayfly hatches are so predictable in timing that experienced anglers can arrive at the stream within minutes of the first emergence.

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.