Flat-headed Mayfly vs Tiny Winter Black Stonefly

Side-by-side species comparison

Attribute Flat-headed Mayfly Tiny Winter Black Stonefly
Scientific Name Epeorus assimilis Capnia nigra
Order Ephemeroptera Plecoptera
Family Heptageniidae Capniidae
Size 10-14 mm 4-8 mm
Habitat Rivers & Streams Rivers & Streams
Diet Herbivores Detritivores
Regions Europe Europe, Northern Asia
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.

Tiny Winter Black Stonefly

A tiny black stonefly that emerges in late winter across European streams. It is among the earliest insects to appear each year.

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Did You Know?

Females are often wingless or short-winged, relying on walking rather than flight to find mates.