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.
One picture of this specimen shows the spinner stage.
This mayfly was collected from Rock Creek in Montana on June 30th, 2010 and added to Troutnut.com by Bnewell on June 29th, 2011.