Fly fishers need to know their insects. I was a slow learner, though, and with good reason. As a boy, I hated bugs. If a creepy-crawly headed my way, I ducked for cover. A spider in my room could reduce me to tears. Mosquitoes were a plague during the sultry Long Island summers of my childhood. I never knew where they’d attack, on the Little League field or at the family barbecue. I was doused with repellent so often I’m lucky I didn’t contract a skin affliction or worse.
So it came as a surprise when as an adult I developed a modest interest in entomology. That happened, of course, when I began trying to match the hatch. At first, I relied on native cunning and made an educated guess at the bugs on the wing, but that guess was usually wrong. What looked like a good imitation to me, judging by the size and color, looked phony to the trout. Would I mistake a Carl’s Jr. Beyond Burger for a Big Mac? Probably not. The same was true of those rainbows and browns. They recognized the difference between Ephemerella dorothea dorothea and Ephemerella invaria, even if I didn’t. For help, I turned to Ernest Schweibert’s Matching the Hatch. First published in 1955, it quickly became the goto authority on the subject. Schweibert revealed a complex ecosystem I’d been looking at, but not really seeing. An architect by trade, Schweibert was a prolific author and passionate conservationist. His encyclopedic Trout, a 1,000-page doorstopper, weighed in at 7 pounds, 5 ounces. Though his prose could be overripe (“It is always the explosive fish we remember, thrust from the river like a mythic sword, like a ballerina tightroping a performance”), his technical advice was succinct and immensely useful on a stream.
With Schweibert as my guide, I headed to the Sierra to conduct my education. Of all the hatches I encountered that summer, mayflies were the most common. They were easy to identify with their lacy wings tilted upward like the sails of a boat. They are the oldest of the winged insects, dating back more than 300 million years. Graceful in flight, they’ve long appealed to writers and artists who see a poetic element in their brief lives. Aristotle and Pliny the Elder remarked on their beauty, while Albrecht Dürer, in his engraving The Holy Family with Mayfly, viewed them as a link between heaven and earth. In England, you’ll find several pubs called the Mayfly, including one on the River Test in Hampshire. I once drank a pint of Burton Ale there, but I couldn’t fish, alas, for lack of a license.
Mayflies proved relatively easy to match, too. I relied on such basic dries as the Parachute Adams, Blue-Winged Olive, and Pale Morning Dun. The hatches were frequent and unpredictable, erupting at times in the middle of the day. The bugs often came off in dense clouds known to entomologists as swarms. “I saw from unseen pools a mist of flies / In their quadrillions rise,” wrote the poet Richard Wilbur in “Mayflies.” Such profusion can spell trouble in urban areas. This past summer in Ohio, for instance, the mayflies arrived in a swarm off Lake Erie and made it so difficult for motorists to see that officials closed a couple of bridges. For fly fishers, a swarm brings only good news. On the North Yuba, I once ran into a cloud of mayflies and hooked half a dozen bragworthy trout in under 30 minutes. Stoneflies operate differently, I learned.
While mayflies stick around from spring through fall, May and June are the prime months for stonefly hatches, although some streams have hatches in April and July — Skwalas, Golden Stones, Yellow Sallies, and the Giant Salmonfly (Pteronarcys californica). The most spectacular hatch of Salmonflies I ever witnessed was on Henrys Fork of the Snake River in Idaho, at the fabled Railroad Ranch in Harriman State Park. Dumb luck landed me there at the height of the season. The big trout were gorging on two-inchlong Salmonflies that hit the water hard enough to cause a little ripple. Even an imperfect cast had a chance of hooking a trophy, given the surface disturbance. I used size 4 Sofa Pillows with lots of bushy hackle — a case where size really did matter.
Hat Creek can usually be counted on for a decent stonefly hatch starting in April, with the peak in May. The stoneflies thrive in clean, cold, fast water, so the Powerhouse riffles always produce, but they’re always crowded with anglers. For peace of mind, I like to fish a meadow stretch or the freestone part of the creek, where the trout hold in pockets and beneath ledges. They might not be so numerous in those stretches, but they tend to be larger than average. If you’ve numbed your brain trying to crack Hat Creek’s complex, small-size hatches, it’s a pleasure to cast a highly visible Golden Stone instead of tying on one tiny fly after another in hopes of scoring. Stoneflies are lousy swimmers and not much better at clinging to trees, so a gust of wind can launch a feeding frenzy among the fish.
Every entomologist, even an amateur, has a favorite insect, and for me, that’s the caddisfly. True, it lacks the impressive size of a stonefly, and it isn’t as elegant or poetical as the mayfly, but it has a trustworthy quality, durable and dutiful without being flashy, that reminds me of the boxers who win decisions by outlasting their opponents. A close cousin of moths and butterflies, the caddisfly split from them about 234 million years ago and evolved into roughly 14,500 species worldwide. As winged adults, caddisflies can live for two to three weeks, an eternity, compared with mayflies, and they’re also hardy and able to survive in less-than-pristine rivers. They’re sexy little devils, too, verging on the promiscuous. The males mate with several different partners eager to receive them, coupling acrobatically in midair.
Caddisflies are the meat and potatoes of a trout’s diet, inviting slashing strikes when they skitter along a stream. Of the countless patterns designed to match them, I stick with the classic Elk Hair Caddis tied by Al Troth, a legendary angler who first experimented with it in 1957. He used the hair of a female elk and bleached it to make it more visible. That remains a selling point — it’s easy to keep track of an Elk Hair Caddis, even in the riffles. It can be dead drifted, skated, or stripped in the surface film. A mere twitch of the rod tip gives it life, and the trout wake up and pay attention.
The king of the caddis family, at least for fly fishers, is the October Caddis (Dicosmoecus gilvipes). According to Gary LaFontaine, it’s among the top three aquatic insects, along with the Salmonfly and Michigan Mayfly (Hexagenia limbata), for catching trophy trout. The October Caddis flourishes in freestone streams and some tailwaters where the current is strong and the bottom is rocky. They’re about an inch long on average, with orange bodies. In spite of their name, they often begin hatching in September in California and may linger into early November. The hatch begins in earnest in the late afternoon and peaks at twilight as the females flop around to lay their eggs. The bugs are almost shy about appearing and stick to the shade, holding in streamside bushes.
I once fished an October Caddis hatch on the upper Sacramento and wish I could head there right now. Autumn is a glorious time in that region, the trees ablaze with color and the air remarkably clear. Although there’s an Elk Hair Caddis variant to match the hatch, my top choice is an Orange Stimulator. The bright body color seems to work as an attractor. Some anglers like to add a pupa pattern on a dropper. Once the egg laying begins, the trout lose their inhibitions and start to feed. In my mind’s eye, I cast an Orange Stimulator to a shady bank, where the lunkers hang out. A sudden breeze comes up and drops an October Caddis into the lap of a trophy brown. I grip my rod and wait for the strike.