Black Mayfly vs Mountain Flathead Mayfly

Side-by-side species comparison

Attribute Black Mayfly Mountain Flathead Mayfly
Scientific Name Ephemera danica var. nigra Cinygmula ramaleyi
Order Ephemeroptera Ephemeroptera
Family Ephemeridae Heptageniidae
Size 15-25 mm body 7-10 mm
Habitat Rivers & Streams Mountains
Diet Omnivores Omnivores
Regions Europe North America
Conservation Least Concern Least Concern

Black Mayfly

A dark color variant of the common Green Drake mayfly found in some European populations. The dark form is more prevalent in upland, acidic waters. Important for trout feeding.

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Did You Know?

The dark form predominates in acidic upland streams while the typical yellow form prefers alkaline lowland rivers.

Mountain Flathead Mayfly

An alpine mayfly restricted to high-elevation cold streams in the Rocky Mountains. Nymphs feed on diatom films on boulder surfaces.

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Did You Know?

This species cannot survive in water temperatures above 15 degrees Celsius.