White Miller Mayfly vs Caenis Mayfly

Side-by-side species comparison

Attribute White Miller Mayfly Caenis Mayfly
Scientific Name Ephoron virgo Caenis horaria
Order Ephemeroptera Ephemeroptera
Family Polymitarcyidae Caenidae
Size 12-18 mm 3-6 mm
Habitat Rivers & Streams Rivers & Streams
Diet Omnivores Detritivores
Regions Europe, Western Asia Europe
Conservation Least Concern Least Concern

White Miller Mayfly

A white-bodied European mayfly that emerges in enormous synchronized swarms at dusk. Females are unique among mayflies in that they moult directly into the spinner stage.

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Did You Know?

Swarms at bridges and streetlights can be so thick they cause traffic hazards.

Caenis Mayfly

One of the smallest mayflies, often called the 'angler's curse' because trout feed on them selectively. Larvae inhabit slow-flowing rivers and lake margins.

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Did You Know?

Caenis mayflies are called the angler's curse because their tiny size makes matching them with artificial flies nearly impossible.