Many serious lake fishermen are well aware of the Chironomid (ki-ron-o-mid), however, I still sometimes hear "chirono-what?" and various other oddities of the English language when I recommend them to people. Basically Chironomids are midges that live primarily in lakes. They are often larger than other midges and can even get as large as size 10 or 8. Most are 18 - 12.
Most lake fish feed heavily and often on Chironomid larva and pupae and sometimes take adults. One of the best ways to fish the larval patterns and pupae is under an indicator simply hanging them and, for lack of a more pc term, "bobber fishing" They can be placed at nearly any depth, even up to 20 feet or more to get them where the fish are. Vary your depth until you find the fish, 4-15 feet are the most common depths I fish.
Some of my favorite flies to fish this way are Chironomid pupae, Bi-color brassies, Zebra midges, Ghost midges, and Blood midges in sizes 18-14. Check out this beautiful cutthroat I caught chironomid fishing this week.