I developed this style of fly pattern to imitate the Pale Morning Dun (PMD) mayfly at its most vulnerable stage—when the dun attempts to escape from its nymphal exoskeleton as it floats in the surface film. At this point, the mayfly is neither nymph nor dun, but a combination of the two. The shuck is often still attached to a body frantically squirming to free itself, and the wings may be fluttering or trapped in the surface film.

Temporarily and often permanently disabled, these crippled insects are an easy meal for selective trout. Unlike traditional patterns that imitate the dun just before it flies to safety (not an attractive proposition for the trout) the Quigley Cripple represents the most edible stage of mayfly dun development.

I first realized the need for a pattern like this 21 years ago while fishing California's Fall River. As in previous years, PMDs were hatching and I had exhausted numerous tippets and changed flies too many times. Large trout ignored my fly completely, while emerging insects were sucked from the surface with reckless abandon. It became obvious to me then, that I needed a low-floating, half-nymph/half-dun mayfly imitation.

The PMD Quigley Cripple solved that hatch for me, but it turned out to be just the first of a series of patterns intended for similar situations (but different hatches) around the country. More of a style of tying than a specific pattern, the only constants are that the rear portion of the fly is tied to imitate the nymph and/or shuck, while the front of the fly hints of the emergence of an adult.

During heavy hatches, trout can afford to be extremely picky about what they eat. Often, they feed exclusively on mayflies caught in the transition between nymph and dun (cripples).

A variety of materials can be used to create this effect, keeping in mind that the half-nymph/half-dun effect requires a fly with a radically different attitude. The hook shank—instead of riding nearly parallel to the surface like a normal dun imitation—bisects the surface film so the rear of the fly is submerged, and the front sits atop the surface film. [Use the links in the black bar at the top of your screen to continue this story. Find out how to tie this pattern with step-by-step instructions, how to create a Cripple to match mayfly hatches on your local waters, and how to fish it effectively. THE EDITOR.]