Medium Olive Duns

Mayflies

Caddisflies

Stoneflies

Scientific Name

Match	Scientific Name
	Acerpenna pygmaea

This common name refers to only one species.

Mayfly Species Acerpenna pygmaea

These are very rarely called Medium Olive Duns.

This species is known in older taxonomies under the former name Baetis pygmaeus.
It is a diminutive baetid with distribution across every region. It is reported to have localized hatches of occasional importance.

Acerpenna pygmaea (Tiny Blue-Winged Olive) Mayfly Nymph

View 3 PicturesThis is a very rare mayfly in western Montana. The shape of the last gill is a key to its identification. I have collected this species in only one location.

Collected May 5, 2007 from in
Added to Troutnut.com by on June 26, 2011

Male Acerpenna pygmaea (Tiny Blue-Winged Olive) Mayfly Spinner

View 8 Pictures

Collected August 1, 2020 from in
Added to Troutnut.com by on August 18, 2020

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