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.
As I prepared to set foot for the first time in the Catskills' storied Esopus Creek, I noticed an Isonychia bicolor nymph crawling out onto a rock at my feet. I pulled out my handy little camera and started snapping pictures.
When mayfly duns pop out of the water and fly away, they aren't yet officially "adults." They have one more step before they're ready to mate: to perch on streamside vegetation and molt one more time into the stage scientists call "imago" and we call "spinner." This article shows step-by-step close-up photos of a Leptophlebia cupida (Black Quill) dun molting into a spinner, and it explains what's going on inside the mayfly.
Guest author Tomaž Modic shares this piece about the history of the "F-fly," a simple but extremely effective fly pattern little known in the states but very popular in its country of origin, Slovenia, and elsewhere in Europe.