Mahogany Dun vs Trico Mayfly

Side-by-side species comparison

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

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.

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.