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.
Like most common names,"Slate Drake" can refer to more than one taxon. They're previewed below, along with 3 specimens. For more detail click through to the scientific names.
An imitation is rarely required, but notes show that when it is needed it is needed badly.