Dark Cahill Dun

The Dark Cahill is a traditional dry-fly pattern created to imitate the darker species of mayflies that hatch throughout late spring and summer, especially in evening light or under overcast skies. It features a lightly tapered body, upright wings, and soft, natural colors that mimic the subdued tones of mature mayflies drifting on the surface. Originally developed as a darker counterpart to the Light Cahill, the pattern became popular in the East and Midwest where tannin-stained waters and shaded streams made lighter flies less visible to trout. Its subtle profile and natural coloration allow it to match a wide range of medium-sized mayflies, making it a versatile “confidence fly” for anglers facing uncertain hatch conditions.

Pair with a Spinner: If refusals begin, consider trailing a spent-wing Light Cahill spinner pattern behind your dry fly for selective fish during the hatch’s tapering phase.