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3. Isoperla nymphs

These two Isoperla nymphs are common in the Russian River in the early part of the year (late January to mid April). As far as I can determine they're Isoperla marmorata and Isoperla mormona. I used Merritt, Cummins and Berg as well as "Nymphs of North American Stonefly Genera" by Stewart and Stark to identify the nymphs to genus. I used Sandberg's "The Isoperla of California (Plecoptera: Perlodidae); Larval Descriptions and a Key to 17 Western Nearctic Species" to identify them to species. http://www2.pms-lj.si/illiesia/papers/Illiesia07-22.pdf .

Sandberg's key is for male larvae and the photos of Isoperla marmorata shown here are female but identification was made with male specimens.

All specimens were in alcohol but the photos were taken within 12 hours of collection so the coloration is accurate.

Nice pics! If you have it, could you give us a ball-park measurement on these?

Thanks!

Spence

Spence, The measurements are in the captions under the photos. 14 mm for I.marmorata and 7-8 mm for I. mormona. The measurements are for body length and don't include the cerci.

How did I over look that?!

Thanks.

Thanks for the link, Mark. Going beyond genus with Stoneflies and Caddis is often much more difficult as access to the literature is not easy or cheap. Kudos for sharing. Stones are especially fun as many if not most have determinative characters that can be identified in photos.

You're welcome. It is harder to find literature on Plecoptera or Trichoptera but there are a few sites that are useful.

For Plecoptera, Illiesia Journal has a wide range of articles on Plecoptera by experts in the field. It can be accessed here: http://www2.pms-lj.si/illiesia/html/papers.html. The only problem with the site is it doesn't seem to have a search function (or I'm missing it) so you have to scroll through a listing of articles.

For Trichoptera, the University of Minnesota has the Trichoptera Literature Database at; http://www.trichopteralit.umn.edu/.

For both plus Ephemeroptera, JSTOR has limited free access to articles. You have to register with them to gain access which can be done here: http://about.jstor.org/rr.

For Ephemeroptera there's Ephemeroptera Galactica. Only problem with it is you need to know the author of the paper you're looking for. It used to have a limited search function but after Michael Hubbard died and the site was administered by others this seems to have disappeared. The articles are here: http://www.ephemeroptera-galactica.com/mfbib.php.

And of course Google, Google Scholar and Google Books are all good scources.



Spence - I did some editing on the captions, so if you were looking then the measurements may not have been there. Or it was brain slippage. :)

Brain slippage...I like that. You are so nice to this old coot! :)

Spence