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.
This specimen seems to be of the same species as a dun I photographed which emerged from another nymph in the same sample.
This mayfly was collected from Paradise Creek in Pennsylvania on May 29th, 2007 and added to Troutnut.com by Troutnut on June 4th, 2007.