**Male Acentrella insignificans (Tiny Blue-Winged Olive) Mayfly Dun Pictures**

Mayflies

Caddisflies

Stoneflies

Classification

Kingdom Animalia (Animals)

» Phylum Arthropoda (Arthropods)

» Class Insecta (Insects)

» Order Ephemeroptera (Mayflies)

» Family Baetidae (Blue-Winged Olives)

» Genus Acentrella (Tiny Blue-Winged Olives)

» Species insignificans (Tiny Blue-Winged Olive)

This specimen emerged indoors from nymphs I had collected, then partly molted into a spinner but got stuck along the way. I've included a couple pictures showing some of the spinner colors. It got a bit waterlogged after emerging, so the wings aren't in perfect shape, but it still represents one of two Baetids that were emerging and drawing trout to rise on the Yakima. Based on body size and shape, it is most likely the same species as this nymph.

This mayfly was collected from the Yakima River on September 12th, 2020 and added to Troutnut.com on September 19th, 2020.

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Male Acentrella insignificans (Tiny Blue-Winged Olive) Mayfly Dun from the Yakima River in Washington

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Jargon Defined:

Nymphs: 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.