Blue Quill vs Small Square-Gilled Mayfly

Side-by-side species comparison

Attribute Blue Quill Small Square-Gilled Mayfly
Scientific Name Paraleptophlebia guttata Caenis luctuosa
Order Ephemeroptera Ephemeroptera
Family Leptophlebiidae Caenidae
Size 6-9 mm 3-6 mm
Habitat Rivers & Streams Ponds & Lakes
Diet Detritivores Omnivores
Regions North America Europe
Conservation Least Concern Least Concern

Blue Quill

A delicate spring-emerging mayfly with bluish-gray body coloring. Nymphs prefer riffles with abundant leaf detritus in clean streams.

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Did You Know?

Anglers consider it one of the most important early-season hatches on trout streams.

Small Square-Gilled Mayfly

A minute mayfly with distinctive square-shaped gills on its nymphs. Adults swarm in enormous numbers near water at twilight.

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Did You Know?

The enlarged second gill plate acts as a protective cover over the remaining delicate gills.