Flat-headed Mayfly vs Embossed Stonefly

Side-by-side species comparison

Attribute Flat-headed Mayfly Embossed Stonefly
Scientific Name Epeorus assimilis Paragnetina immarginata
Order Ephemeroptera Plecoptera
Family Heptageniidae Perlidae
Size 10-14 mm 18-25 mm
Habitat Rivers & Streams Rivers & Streams
Diet Herbivores Predators
Regions Europe North America
Conservation Least Concern Least Concern

Flat-headed Mayfly

A stream-dwelling mayfly nymph with a flattened body for clinging to rocks in rapids.

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Did You Know?

Its flattened nymph shape allows it to live in the boundary layer of fast currents.

Embossed Stonefly

A large patterned stonefly of clean eastern streams with raised body markings. Nymphs are top predators among stream cobble invertebrate communities.

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Did You Know?

Nymphs moult up to 30 times before reaching adulthood, far more than most aquatic insects.