As always happens in such situations, we used far different flies, Rick’s being a newer-fangled CDC emerger dressing, mine a more traditional olive Sparkle Dun. But as also always happens, neither of us had any need to rush back to the car, or worse to the nearest fly shop, several hours away, to arm ourselves with flies that would solve something as common as a blue-winged olive hatch. Imitations for them are always aboard, and in this case gave us an extended afternoon of fishing as good as we’d have gotten had we researched the hatch, tracked it down, driven many miles to meet it, rather than running into it entirely by accident. We had that hatch to ourselves. All the smart anglers were gathered elsewhere, fishing the same hatch on more famous waters.
In an earlier article, I discussed how to select a set of flies that fits into a single medium-sized fly box, but covers the most common insect hatches you’ll find, across our continent and on any other (see Winter 2018, “Condensing Flies”). In essence, you select a pattern style to match mayfly duns, tie it in the most common colors in which those duns arrive—olive, sulfur, and mahogany—each in the range of sizes most common for those colors.
For olives, that’s from small 20s up to large 12s, for sulfurs, 18s to 14s, for mahoganies just 16s and 14s. That’s not a lot of Sparkle Duns or Parachute Duns to fit into a fly box, but it covers more than three-quarters of the mayfly duns you might encounter, anywhere in the world that trout eat them.

The same applies to caddis. A single pattern style—let’s say the great Hans Weilenmann’s CDC and Elk, tied in natural tan and medium gray, each in a range of sizes from 12 to 18—comes close enough to almost any caddis to fool almost any trout feeding on them. Of course, there will be frustrating exceptions—the monstrous fall caddis, for example—but specialty cases are why you keep an empty row in that fly box.
You can treat the stoneflies with variations on a Foam Stone in dark and size 6 and 8 for the giant salmonflies, gold in size 8 and 10 for the golden stones, and yellow in size 14 and 16 for yellow sallies. That’s about it. Larger Skwala and smaller little brown stones are special cases for which you acquire and carry flies only if you bump into them often enough to demand matches.

Midge imitations, like Model T Fords, can be tied in all sorts of colors, but you’ll find adequate success if you tie them only in black, and only as pupae. The Zebra Midge, in sizes 12 down to 20 will solve a surprising number of midge situations, even when the natural is not near it in color.
Foam Beetles in 12 to 18, and Foam Ants in 16 to 20, both in black, round out a selection of dry flies that allow you to match most hatches, in most places. A box so simply outfitted will not solve all your problems. But it will free you up from the need to restrict yourself to crowded moments on famous waters, during known hatches. Instead, this box enables you to adventure out, and run into surprises wherever you might find them.

Surprisingly enough, the same set of flies will work on those famous waters as well.
Dave Hughes is coauthor with Rick Hafele of Western Mayfly Hatches, author of Pocketguide to Western Hatches, Handbook of Hatches, and Essential Trout Flies.