Tying a Light Cahill
From the middle of May to September, depending on where you live, hatches of different varieties of light colored mayflies now commonly known as Light Cahills can be found. This is a recent collective common name that covers many groups of the Heptageniidae family of mayfly insects. In the 1880′s a New York railroad worker called Daniel Cahill developed a fly that became famous all over America, the Light Cahill. When he wasn’t fishing or tying flies he was a brakeman on the old Erie and Lackawana Railroad. It is a great general imitation of summer mayfly duns. Just choose the hook size and color to match your local hatch. It was originally designed to imitate a family of mayflies with the name of Stenonema. They begin hatching in late May and continue through June. In smaller sizes the Light Cahill is a useful fly to imitate hatches of Pale Morning Duns, Pale Watery Duns, Spurwings, Pale Evening Duns and the Red Quill Mayfly. The Pale Morning Dun (PMD) hatch is normally in the summer and massive in numbers, triggering aggressive trout feeding. The hatch normally happens in slow, clear water. The PMD is normally best matched with a size 18 hook fly. The Red Quill mayfly is not as widespread as other mayflies but if they live in the river you are fishing, you will find that this fly is an important insect to have imitations of. The reason being is that they occur in large numbers when they hatch and these are the flies that the trout want. Hatches are normally in the afternoon.