And another new find: Ephemerellidae (Spiny Crawler Mayfly), Drunella lata

In early June, I went fishing in western Virginia -- Cow Pasture River -- and of course, I had to look for some insects.  Very happy to find this one, since I knew right away it was a Drunella nymph I had not seen before.  It turned out to be Drunella lata.

Drunella nymphs have robust fore femora with a jagged leading edge, something you can obviously see in this photo.  But what about the species?  Let's look at Steven Beaty's description ("The Ephemeroptera of North Carolina," p. 48). 

Nymphs 6-7 mm; head smooth with short, flattened lateral frontoclypeal projections which are about as long as wide; femora with few or no long, fine setae on posterior margin; abdomen without paired dorsal tubercles although diverging low ridges may be present on 3 or 4-8, becoming successively more parallel in posterior segments; dorsum brown with tergum 8 mostly pale; posterolateral projections on 4-8 and apices of femora pale; mature nymphs often with pale area tinged with red; ventral surface light brown.  Collected in February through July in the Mountains.

This nymph measured 7 mm. I didn't bother to take a close-up of the posterior margins of the femora, but certainly no setae are visible in the photos I've taken.  For the rest of the features, let's take them in order.

1) the smooth head, i.e. no tubercles on top like those we see in Drunella tuberculata (second photo below)

vs.

2) the short, flattened frontoclypeal projections, 

3) the diverging low ridges on sterna 4-8 (hard to see if they are progessively parallel?)

4) brown dorsum, with tergum 8 pale, and the pale apices of the femora and the pale areas on the femora which are tinged with red,

5) posterolateral projections on segments 4-8,

and 6), the ventral surface being light brown,

Pretty cool looking critter!  Drunella lata.

Oh, I also found a very pretty stonefly nymph, Agnetina flavescens.