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.
Just got an unpublished manual by Jacobus, Wiersema and Webb on ID of western and northern mayflies for a SAFIT workshop. Given the state of taxonomy on Epeorus they've opted to lump E. albertae, E. dulciana, E. hesperus, E. lagunitas and E. margarita into something called the Epeorus albertae group.
Yes, that is an excellent resource! Luke Jacobus is a good friend and fellow contributor here. He goes by Konchu. Jeff Webb also contributes and goes by Jmw975.
I can see I'll have to step up my game here.
Mark
The only constant is change, but for the last several years these tiny mayflies have been the dominant Summer hatches on the middle reaches of Fall River. It has gone unreported (or rather misreported as PMD hatches). They provide excellent fishing hatching midday for several hours. They are on the water in significant numbers from late July through to Fall until the baetids & Mahoganies take over. When you hear reports of little PMD's out West below size 18, suspect these little guys as the culprits.