March Browns and Cahills

Many of America's traditional flies, like the March Brown and the Light and Dark Cahills, originated in the Catskills to imitate the mayflies of this genus. Back then most they were in classified in Stenonema, the name by which many anglers still know them. Caucci and Nastasi wrote of them in Hatches II:

"There is a matrimony between Stenonema flies and Catskill rivers that is as synonymous as ham and eggs."

By far the most important species is Maccaffertium vicarium. Of the others, Maccaffertium ithaca is the most important, and Maccaffertium modestum and Maccaffertium pulchellum are also reported to produce localized fishable hatches. These lesser species amount to much of the sporadic Light Cahill hatching in evenings throughout the summer.

Anglers looking for information on the popular species Stenonema fuscom should know that it has been combined with Maccaffertium vicarium.