Miniature Blue-Winged Olives

Mayflies

Caddisflies

Stoneflies

Scientific Name

Match	Scientific Name
	Acentrella

This common name refers to only one genus.

Mayfly Genus Acentrella

These are often called Miniature Blue-Winged Olives.

The only Acentrella species commonly reported to be important to anglers is Acentrella turbida, though Acentrella insignificans is important in some western locales. See the species pages for distribution and timing details. This genus is one of two (including Heterocloeon) that can easily be distinguished from other Baetidae genera by the presence of a conical mesonotal projection (Conical mesonotal projection: small cone shaped spike sticking up from the top and front part of the middle thorax segment.). A. turbida lacks hindwings which is useful for distinguishing this species from all others in either genera. A. turbida was previously known by the names of its synonyms (Synonym: A former name of a taxon, usually a species. Entomologists frequently discover that two insects originally described as different species are one in the same, and they drop one of the names. The dropped name is said to be a synonym of the remaining name. These changes take a while to trickle into the common knowledge of anglers; for example, Baetis vagans is now a synonym of Baetis tricaudatus.) Pseudocloeon turbidum in the West and Pseudocloeon carolina in the East.

Male Acentrella insignificans (Tiny Blue-Winged Olive) Mayfly Nymph

View 10 PicturesAnother nymph probably of the same species as this one emerged and was photographed as a dun and partly-molted spinner.

Collected September 12, 2020 from in
Added to Troutnut.com by on September 19, 2020

Female Acentrella (Tiny Blue-Winged Olives) Mayfly Dun

View 3 PicturesI've lost the date information for this specimen and taken a guess.

Collected August 1, 2004 from in
Added to Troutnut.com by on January 25, 2006

Female Acentrella turbida (Tiny Blue-Winged Olive) Mayfly Spinner

View 12 Pictures

Collected July 17, 2017 from in
Added to Troutnut.com by on July 24, 2017

See 4 more specimens...

Jargon Defined:

Conical mesonotal projection: small cone shaped spike sticking up from the top and front part of the middle thorax segment.

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.

Nymph: The juvenile, underwater stages of mayflies, stoneflies, dragonflies, and damselflies and other aquatic insects whose juvenile stages are covered by hard exoskeletons. The word can also refer to the fishing flies which imitate these creatures, in which case it is used as a blanket term for flies imitating any underwater stage of an invertebrate (except for crayfish and leeches).

Spinner: There are two winged stages of adult mayflies. They emerge from the water as duns, molt on land (usually) into their fully mature stage, spinners. As spinners, they mate, lay eggs, and die.

Synonyms: A former name of a taxon, usually a species. Entomologists frequently discover that two insects originally described as different species are one in the same, and they drop one of the names. The dropped name is said to be a synonym of the remaining name. These changes take a while to trickle into the common knowledge of anglers; for example, Baetis vagans is now a synonym of Baetis tricaudatus.