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.
Of course, it turned out that George hadn't invented the damn thing at all, it was just #5,091 out of the 9,717 lies he told in that book alone.
I was well into my 20's before experience undid most of the informational damage George Herter did to my fishing knowledge.