Tiny Baetis mayflies are perhaps the most commonly encountered and imitated by anglers on all American trout streams due to their great abundance, widespread distribution, and trout-friendly emergence habits.
I collected this specimen along with a female dun of the same species. Unfortunately it's not in very good shape.
After poking at it for a while under a microscope with a good scientific key in hand, I'm pretty sure this is either Leptophlebia cupida or Leptophlebia nebulosa. I can't tell which.
This mayfly was collected from Factory Brook in New York on May 9th, 2007 and added to Troutnut.com by Troutnut on May 18th, 2007.