Trico Mayfly vs Mahogany Dun

Side-by-side species comparison

Attribute Trico Mayfly Mahogany Dun
Scientific Name Tricorythodes stygiatus Isonychia harperi
Order Ephemeroptera Ephemeroptera
Family Leptohyphidae Isonychiidae
Size 3-6 mm 13-17 mm
Habitat Rivers & Streams Rivers & Streams
Diet Detritivores Omnivores
Regions North America North America
Conservation Least Concern Least Concern

Trico Mayfly

A tiny mayfly that forms enormous morning spinner falls over calm streams and rivers. Males have distinctive white bodies with black thoraxes.

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Did You Know?

Trico spinner falls create such dense blankets of spent mayflies on the water surface that trout gorge themselves to satiation.

Mahogany Dun

A large reddish-brown mayfly with impressive filter-feeding forelegs. Nymphs prefer moderate to fast riffles with clean gravel substrates.

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Did You Know?

Adults hold their forelegs forward in flight, making them easy to identify on the wing.