Little Western Blue-Winged Olives

Mayflies

Caddisflies

Stoneflies

Scientific Name

Match	Scientific Name
	Attenella margarita

This common name refers to only one species.

Mayfly Species Attenella margarita

These are sometimes called Little Western Blue-Winged Olives.

Though having a national distribution, this species is considered by angling authorities to be important only in the West. In localized waters where it is abundant, it can be a significant hatch.

Attenella margarita (Little Western Blue-Winged Olive) Mayfly Nymph

View 7 PicturesNotes from the microscope on the ID: Maxillary palp (

The palp on the maxilla of an Ephemerella nymph (detached and photographed under a microscope) is highlighted in red here.

Palp: A long, thin, often segmented appendage which can protrude from certain insect mouth parts such as the maxillae. Also known as the < />palpus.) is present, distinctly 2-segmented, but very small. Gills on segment 4-7. This specimen has some unfortunate damage to the abdomen, but it's the only one I found in my sample.

Collected August 3, 2020 from in
Added to Troutnut.com by on August 19, 2020

Female Attenella margarita (Little Western Blue-Winged Olive) Mayfly Dun

View 6 PicturesI found this dun unusually late in the year for anything in the Ephemerellidae family in the East. It's also small for that family.

Collected September 4, 2006 from in
Added to Troutnut.com by on October 3, 2006

Jargon Defined:

Abdomen: The rear and usually the longest (ten-segmented in mayflies) portion of an insect's body, to which the tails are attached.

Dun: Mayflies have two adult stages. They first emerge from the water as duns (scientifically known as the subimago stage). They then molt into the spinner (imago) stage, in which they mate and die. Sometimes the word "dun" is confusingly used to refer to a brownish gray color in fly tying materials.

The palp on the maxilla of an Ephemerella nymph (detached and photographed under a microscope) is highlighted in red here.

Palp: A long, thin, often segmented appendage which can protrude from certain insect mouth parts such as the maxillae. Also known as the < />palpus.