Light Cahill Mayfly vs Swamp Metalmark

Side-by-side species comparison

Attribute Light Cahill Mayfly Swamp Metalmark
Scientific Name Heptagenia solitaria Calephelis mutica
Order Ephemeroptera Lepidoptera
Family Heptageniidae Riodinidae
Size 9-13 mm 22-28 mm wingspan
Habitat Rivers & Streams Wetlands
Diet Omnivores Omnivores
Regions North America Upper Midwest United States, Great Lakes region
Conservation Least Concern Near Threatened; extremely local

Light Cahill Mayfly

A pale-colored mayfly highly prized by fly fishers for imitating hatches. Nymphs prefer moderate current over gravel substrates.

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Did You Know?

The Light Cahill dry fly pattern, designed to mimic this species, has been used since the 1880s.

Swamp Metalmark

A rare and localized metalmark butterfly of midwestern wetlands with warm rusty-brown wings marked with fine metallic lines. It has very specific habitat requirements.

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Did You Know?

Some populations consist of fewer than 50 individuals, making it one of North America's most vulnerable butterflies.