Identification, Images, & Information
For Insects, Spiders & Their Kin
For the United States & Canada
Clickable Guide
Moths Butterflies Flies Caterpillars Flies Dragonflies Flies Mantids Cockroaches Bees and Wasps Walkingsticks Earwigs Ants Termites Hoppers and Kin Hoppers and Kin Beetles True Bugs Fleas Grasshoppers and Kin Ticks Spiders Scorpions Centipedes Millipedes

Upcoming Events

Spring 2021 gathering in Louisiana, April 28-May 2

National Moth Week photos of insects and people. Here's how to add your images.

Photos of insects and people from the 2019 BugGuide Gathering in Louisiana, July 25-27

Discussion, insects and people from the 2018 gathering in Virginia, July 27-29

Photos of insects and people from the 2015 gathering in Wisconsin, July 10-12

Photos of insects and people from the 2014 gathering in Virginia, June 4-7.

Photos of insects and people from the 2013 gathering in Arizona, July 25-28

Photos of insects and people from the 2012 gathering in Alabama

mayfly - unident - Ephemerella invaria

mayfly - unident - Ephemerella invaria
Selkirk/Brauer Field Station, Albany County, New York, USA
June 24, 2015
Size: 10 mm +/-
Came to lights.
No better photos. Dump if need be.

Moved from Mayflies.

This photo poses a particularly difficult challenge, at least for me.

It appears to have only 2 tails, but of course, a third tail could either be missing or simply not be in view. It appears to have streak of pigmentation (vittae) on the posterior half of the leading edge of the fore wings. It appears to have normal sized hind wings.

Putting those clues together leads me to suspect this female imago is either Heptageniid genus Epeorus, or Ephemerellid genus Eurylophella, or some obscure genus with which I am not familiar.

Thanks. Too bad I couldn't g
Thanks. Too bad I couldn't get a better photo. This thing was small and too active.

Body length

I assume the estimated size of 10 mm does not also include the length of the tails. Is that correct?

You are correct.
You are correct.


Have requested a 2nd opinion from a fellow aquatic insect enthusiast; will share his opinion once received.

Ephemerella invaria
Kurt Schirmer, my fellow aquatic insect enthusiast friend commented as follows: Looks like Ephemerella dorothea to me, though missing a tail. Interesting variation of pigmentation in the stigmatic region.

However, after further study on my part, I am leaning toward Ephemerella invaria, where I will place it in the guide.

Comment viewing options
Select your preferred way to display the comments and click 'Save settings' to activate your changes.