MAYFLIES

This fly is the most important insect that fish feed upon. These flies vary in color from slate gray to almost pure white. These mayflies emerge when the temperature, and other conditions are met that permit them to complete their life cycle.

Mayflies hatch about noon during the winter; during the early morning and late evening in the spring and summer, and at night during the hot summer days. Some of the best times to find a hatch in the spring and fall is on those blistery days when it snows a little, and then the sun breaks through. Never pass up a good duck day if you want to enjoy some excellent fly fishing in the spring or fall.

It is enough to know that an adult mayfly begins its life cycle as a nymph, and that trout feed far more on mayflies as nymphs than as duns or spinners. It is a simple matter of availability.

The life cycles of stream insects are vitally important to the angler. It is always helpful to know that dark insects--the blue-gray duns, the little black stone flies--are early season flies; that the brown flies appear a bit later in the spring, that the pale, light-colored flies come still later and on into the summer. The Provo River has a hatch of brown caddis flies later on in the summer, but generally this rule holds true.

A. Nymphs: Mayfly nymphs are 10 segmented and may be either the free swimming or the crawling type. They vary in size from about a size 8 to a size 18 or 20 (hook size, not shoe size).

B. Emerger/Dun: This stage is the most important as far as the dry fly fisherman is concerned, for these mayflies are just hatching from the nymph stage. They usually float along on the surface drying their wings. These mayflies with their clumsy attempts to fly send the fish into a feeding frenzy, and often it seems impossible to scare fish that are feeding on duns.

C. Spinner: Many anglers mistakenly call a spinner fall, a hatch. These flies are those that have hatched some time before and are returning to the stream to drop their eggs. Although spinners are not as important as the nymph or dun stage, a good spinner fall is a sight to behold, for these flies will be dancing over the water in a flight that gives them their name.

Spent wing flies are a must during a spinner fall.