**Male Epeorus (Little Maryatts) Mayfly Dun Pictures**

Mayflies

Caddisflies

Stoneflies

Classification

Kingdom Animalia (Animals)

» Phylum Arthropoda (Arthropods)

» Class Insecta (Insects)

» Order Ephemeroptera (Mayflies)

» Family Heptageniidae (March Browns, Cahills, Quill Gordons)

» Genus Epeorus (Little Maryatts)

I hoped this dun would molt into a spinner for a positive ID, but it didn't. My best guess is Epeorus dulciana, but that's only because that's the smallest western Epeorus species, and this specimen is smaller than any of the others, with a body length of 5.3 mm (although it would be longer as a spinner) and a wing length of 8.5 mm.

It was collected at the same time as a similar-sized female dun.

This mayfly was collected from the South Fork Sauk River on July 5th, 2017 and added to Troutnut.com on July 6th, 2017.

View Full Size and Comment (3.3X larger)

Male Epeorus (Little Maryatts) Mayfly Dun from the South Fork Sauk River in Washington

View Full Size and Comment (3.9X larger)

View Full Size and Comment (3.5X larger)

View Full Size and Comment (2.2X larger)

View Full Size and Comment (2.5X larger)

View Full Size and Comment (2.1X larger)

Tick marks are 1/16"

View Full Size and Comment (3X larger)

View Full Size and Comment (3.1X larger)

View Full Size and Comment (3X larger)

View Full Size and Comment (2.5X larger)

View Full Size and Comment (2.7X larger)

View Full Size and Comment (3X larger)

Recent Discussions of this Dun

ID on this one?

Posted by Troutnut on Jul 6, 2017

See the caption for the specimen -- I'm thinking Epeorus dulciana based on size and geographic distribution alone, but I can't find any information about how their duns look. Pretty mayfly, though!

Start a Discussion of this Dun:

You must log in at the top of the page to post. If you haven't registered yet, it's this easy:

Jargon Defined:

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.

Molt: When aquatic insects with hard exoskeletons (like mayfly and stonefly nymphs) grow bigger, their exoskeleton does not grow with them. Instead they grow a new, larger one underneath and shed the old one when it's too small. This process is called molting.

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.