How large? Well, on British Columbia's celebrated Kamloops lakes, flyfishers take good numbers of 5-plus-pound trout on chironomid patterns each year.

As for your scrutinizing the eye of the hook, fly shops sell clip-on magnifying glasses to help you do that. For you older guys, there's also an interesting new product called the 20/20 Magnetic Tippet Threader.

For winter flyfishers, midges' most important characteristic is that in waters that don't freeze, they are available to trout year 'round.

Most sub-aquatic insects emerge as adults between spring and late autumn. But different broods of chironomids will hatch throughout the year on the same body of water.

Moreover, there are hundreds of different species of midges, and they can be phenomenally abundant on fertile, low-elevation lakes.

This year-round availability and potential for large numbers make them an important food source to trout. Though every body of water is different, research has shown that in lakes, chironomids are usually the most important to trout before and after other species of insects hatch. In most areas, that means in winter.

Chironomids have what is known as a "complete" life history, with four stages of development: egg to larva to pupa to adult.

In many species of chironomids, the larvae live in tubes in mud at the bottom of lakes, often in bewilderingly high numbers. When they have pupated and are ready to emerge into the air, the insects swim to the surface in a protective pupal husk. They then hang beneath the surface film in a vertical position and they emerge from their husks as adults.

After their wings harden, the adults mate, and the females return to lay their eggs on or under the water.

PATTERNS FOR CHIRONOMIDS
It took the vast majority of fly-tiers quite a while to set their sights on midges. Historically, fly-fishing was utterly dominated by the mayfly.

This tradition began in Great Britain, where the slow, weedy chalk streams of southern England produced virtual blizzards of mayflies and where brown trout had the time to scrutinize them selectively before striking.

When North American anglers began to expand the contents of their fly boxes beyond the bright attractor patterns they'd used for brook trout, they adopted the theories of the English writers and focused nearly exclusively on mayflies.

In Ray Bergman's classic book Trout, first published in 1938, he makes scant mention of flies other than the Black Gnat, which can imitate midges in small sizes.

More recently, fly-tiers have focused their attention on the other two dominant subaquatic insects: caddisflies and stoneflies.

There has been some serious work directed at midge fishing, most notably by Ed Koch and Ed Engle. But if you examine any contemporary fly-fishing catalog, you'll find dozens of patterns created to imitate the "big three" insects, and only a handful that represent chironomids.

If you fall under the thrall of midge fishing, especially winter midge fishing, you will join a small but growing fraternity (or sorority) of flyfishers.

For several decades now, the Griffith's Gnat has been the most popular imitation of an