I'm guessing at the length. I didn't measure it. But it was visibly larger than several Baetis nymphs also netted this morning (4/26/2013). This photo doesn't show it well. But this nymph does have fine fan-like gills on the sides of each abdomen segment. Perhaps I should try photographing over a light blue background. This image was made with a microscope, which has no depth of field. I might try remaking the photo with a bellows between camera and macro lens, so I could use F-22 instead of F-0. In order to get a bit more depth of field.

This is an edit to my original comment. I think this must be a micro stonefly. It is perhaps 1/4 again longer than the body length of a Baetis mayfly. Which is still very small. But it does have the two cercae (tails) and the prominent wing cases of a stonefly. Long abdomen too.