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.
Here's a Baetid nymph close to hatching, with darkened wingpads. It's got dark bands on the tail at the middle and tip, a rounded, oval 7th gill, and gill veinlets which are visible but not conspicuous.
This mayfly was collected from unknown in Wisconsin on August 8th, 2004 and added to Troutnut.com by Troutnut on January 25th, 2006.