Light Cahill

Overview: The Light Cahill (Stenacron interpunctatum) is a quintessential mayfly that signals the heart of the fly fishing season. Known for its delicate pale-yellow body and clear, gossamer wings, it thrives in cold, oxygen-rich streams and rivers. Emerging in late spring and early summer, this mayfly is particularly active during evening hatches, drawing trout to the surface with its elegant rise. Its predictable emergence and visibility in low light make it a go-to hatch for anglers targeting rising fish during the golden hours of the day.

Emerger Stage: The emerger stage of the Light Cahill is a critical time for anglers to imitate, as the nymphs transition to adults just below or at the water's surface. These insects are often suspended in the film with trailing shucks, making them highly vulnerable to trout.

Adult Stage: The adult Light Cahill ranges from 1/2 to 3/4 inch in size, with creamy-yellow bodies and translucent, lightly veined wings. Dry fly patterns tied on hooks size 12–16 best replicate them. Look for evening rises during their emergence, and focus on soft seams and pools where trout sip adults from the surface. Spinners are also effective during the final stages of the hatch at dusk.