Midge larvae are found in all types of water, though those in stillwaters tend to be larger than those found in streams. They live on, or burrow into, the substrate and feed on algae or decaying plant and animal matter, though a few species prey on smaller insects.
Since Midge larvae are available all year you can fish their imitations anytime you feel like trying one on your leader. But some months are better than others. Trout usually feed heavily on Midge larvae; from late spring to early fall, however, their importance may be overshadowed by other insects.
When Midge larvae reach maturity, they hide on the bottom among debris or in burrows, or spin cocoons and begin pupation. Normally within a week, the pupae are fully developed and ready to leave the bottom.
Trout are so accustomed to seeing Midge pupae floating by that most fish eat them with little thought or caution. Anytime of the year during the daylight hours that a stream is fishable, you should be able to catch trout on a Midge pupae pattern.
Midge adults emerge all year in streams that remain ice-free during the winter months. Emergence occurs during the daylight hours. Leaving the bottom, the pupae swim and float to the surface where they push through the surface film and the adults emerge.
Even when adults are emerging, trout normally take the pupae, which are more easily captured. But if the adults stay on the water long enough, or are crippled, trout have an opportunity to feed on them. Use a floating adult pattern like a Griffith's Gnat or Stillborn CDC Midge on these trout.
