White Miller Mayfly vs Blue-Winged Olive

Side-by-side species comparison

Attribute White Miller Mayfly Blue-Winged Olive
Scientific Name Ephoron virgo Baetis tricaudatus
Order Ephemeroptera Ephemeroptera
Family Polymitarcyidae Baetidae
Size 12-18 mm 5-9 mm
Habitat Rivers & Streams Rivers & Streams
Diet Omnivores Omnivores
Regions Europe, Western Asia North America
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.

Blue-Winged Olive

A small olive-colored mayfly with distinctive bluish-gray wings, abundant in clean streams across North America. It produces multiple generations per year.

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Did You Know?

Blue-winged olives are among the few mayflies that hatch in winter, providing vital food for trout during cold months.