The Black Gnat Dry Fly most likely evolved as a dry fly adaptation of a very old British wet fly pattern. Whatever its origins, it has been a standby fly of savvy dry fly anglers for decades. The Black Gnat is a great dry fly for early morning or late evening fishing, or on overcast days when the dark silhouette seems to be readily visible to rising trout. Two useful variations are the Red-Tailed Black Gnat tied with red hackle fibers for the tail, and the Black Gnat Special, which substitutes red floss for 1/3 of the rear body in addition to red hackle fibers for the tail.