I have a question. Here's the section on the Caddis -
In the caddis family, the longest underwater stage is the larva, unlike the mayfly. A caddis larva essentially looks like a maggot, with a soft, often off-white body with no legs on it, usually a dark head, and with a couple of short short legs right behind the head that it uses to hold on to rocks with. Some caddis species have green, even bright green bodies, and are often called "green rockworms". In many caddis species the larva build cases out of sand, pebbles, sticks, and other debris, and the only thing that ever sticks out of the case is their head. Others are free-living. Both cased and non-cased caddis larva occasionally become loose and available to fish for food, and I'm sure they are softer and tastier than other nypmhs :-), so trout will often readily take a caddis larva pattern. When ready to become an adult, the larva essentially cacoon themselves like moths or butterflies, and go through a pupal stage. During this time they are of no importance to fisherman. At the time of hatching, though, the pupa crawls out, and swims for the surface so it can hatch to an adult. This is a very important stage for fisherman, and emerger fishing in a caddis hatch can be very good. Caddis adults only have one stage. The adults have short bodies that are completely hidden (from above) by tent-shaped wings (not dome tents, but the old A-frame tents), no tails, and very long, pronounced antennae. Caddis adults often skitter (or "motorboat") across the surface as they are drying and waiting to fly off -- even more often on lakes. In depositing eggs, most caddis species swim below the water, and so offer wet-fly imitation to be effective. They do not tend to die near or on the water, unless eaten by a fish, of course.
During this time they are of no importance to fisherman.
Why is this? I'd think this is the stage we'd use a zebra midge.