I believe I’d find very little disagreement among fly fishermen if I stated that, “The broad general definition of a wet fly is a fly designed to be fished in the water; and a dry fly is a fly designed to be fished on the water.”
I could probably also define it as: Wet flies you want to get wet (i.e. waterlogged) and dry flies you are trying keep from getting wet.
Sounds simple enough doesn’t it? But that is likely to be where the consensus on this topic will end, and if I get any more specific, I’ll likely find more and more resistance (opposition) to any definition I might offer. But not being one to cave into peer pressure, I’m going to go out on a limb here and state emphatically:
“A dry fly is a fly designed to sit atop the water column, and imitate the winged adult form of an aquatic insect.”
Oh, I can hear the groaning coming from my monitor already, and I haven’t even posted this yet.
Now before you go getting too upset with me, carefully consider that statement. Is your favorite dry fly an Adams, Elk Hair Caddis, Blue Winged Olive, or Griffith’s Gnat? No problem, they all qualify under that definition. Perhaps you lean more towards the Humpy, Royal Wulff, Stimulator, or Royal Coachman. Once again… no problem. These attractor patterns may not be designed to imitate a specific aquatic insect, but they do (roughly) represent a variety of them. Like I said, there is no issue here.
Where there may be an issue is with the flies that make the transition from water to air. Namely the Emergers. Emergers just can’t decide if they’re going swimming or not. They’re kind of like those pretty girls that get in the pool, but never actually get their head wet. You might think that because of this the emergers would be scorned by both the wet fly fisherman and the dry fly fisherman. But just as with those pretty girls, you won’t hear many fly fishermen complaining about them. Indeed, the opposite seems to often be true. Both camps (wet and dry) will often utilize emerger patterns, even though the real purists in either camp may not consider them as part of their own. And that in and of itself is probably reason enough to not consider them true dry flies. But even without considering that sentiment, a dry fly should be dry. Not half wet. So while I certainly fish emergers, I have to admit, they aren’t technically a true dry fly.
Another category of flies that I’m sure there are more than a few taking issue with me on are the Terrestrials. I can see why they would consider them as dry flies, and again, I fish them as well. But it’s a slippery slope were standing on if the only criteria for being a true dry fly is that it floats. Consider the popper, mouse patterns, or other surface lures. An individual could make a pretty strong argument for them based solely on their floating ability, but I certainly don’t consider them dry flies, and here’s why.
If I stop to consider how a fly is designed, and how it is designed to be fished, one thing stands out pretty clear to me: True dry flies are designed for, and typically fished with, little or no action. If I’m dead drifting an ant pattern, I’m probably fishing it more as a midge than an ant. Yet make a terrestrial “struggle” like a drowning bug, and they come to life. That’s how (what) they were designed to imitate. The same holds true for the other surface lures I mentioned. They are all designed to be fished with a lot of action. Just think of them as Streamers that float. And I don’t think I’ve ever heard a fly fisherman claim that a streamer is a dry fly. Sure, (unlike poppers) terrestrials are often dead drifted as well. But if I’m honest about it, even though I fish terrestrials (I don’t fish poppers etc.) I don’t really consider them to be a true dry fly.
So there you have it. My take on what makes a dry fly, a dry fly.
Now you may let me have it.