This Caddis Emerger is kind of a guide-fly version of LaFontaine's Sparkle Emerger. It's easy to tie, uses few materials and is remarkably effective.
Rather than Antron or Zelon for the sheath or bubble, I'm going to use some white New Zealand sheep wool that comes with the now widely available New Zealand Strike Indicator kits. Yes, the wool works great as an indicator, but it also has some properties that make it a fabulous fly tying material. As you can see here, when it's wet, it has a really nice translucent quality which is perfect for this pattern.
For a hook, a Dai-Riki #300 in size 16 is a good choice. It's an eye length longer than the 305 which helps with the proportions on this fly. Start by mashing the barb and then getting the hook firmly secured in your tying vise.
For thread, it's hard to go wrong with olive 6/0 Danville Flymaster. Start your thread between 1/3 and 1/2 a hook shank length behind the eye. The location is pretty critical. Continue taking wraps rearward before breaking or snipping off the tag. Then take a few more wraps back to about the hook point.
From a clump of wool, pull out a small pinch of fibers. They should be long enough so they can be folded over to double the size of the pinch. This helps to save a little wool. Snip off the fold square while holding the fibers tightly between your finger tips. With a pinch wrap, secure the wool to the hook, making sure the fibers don't extend forward of the thread tie-in point. Continue taking securing wraps. As you start to work rearward, push down on the clump to roughly split it in half with the bend of the hook. Keep doing this while you wrap rearward. The idea is to completely encircle the hook shank with wool fibers. You can then take wraps forward in preparation for dubbing.
Here I'm going to use brown rabbit fur but tan and green also work well. You don't need much dubbing, just enough to cover the thread wraps you've already made. This will form the underbody of the fly which will show through the translucent wool. The dubbing should stop right at the end of the thread wraps.
Next, advance your thread all the way to the eye in one long open spiral. The purpose of this will become evident soon.
Split the wool roughly in half and pull both sides forward to completely surround the dubbed underbody. This really doesn't have to be perfect. While pulling the wool forward, take 3 or 4 wraps of tying thread right behind the eye then lift the wool to vertical and pull backwards to inflate the wool bubble. That open spiral thread wrap is what allows you to do this. Take a few wraps directly around the hook shank and then a few more over top of the wool. This is slippery stuff and needs to be secured well. You can then reach in with tying scissors and snip the wool off close. Take a few more thread wraps to cover up the butts. If everything went according to plan, you should end up with a nice little bubble that completely surrounds the hook.
Hungarian Partridge is used to represent the legs, emergent wings and antennae. Select a feather with fibers about 1 1/2 hook shanks in length. Strip off the fuzzies from the lower part of the stem, and then get hold of the very tip of the feather and pull the lower fibers down to expose just the tip. Cut it off, leaving a small triangle as an anchor. Place the feather against the near side of the hook with the dull or back side facing away from you. Take thread wraps over top of the anchor to firmly secure the feather to the hook. Get hold of the bare stem with hackle pliers and begin taking wraps. Notice how the fibers tend to curve rearward, this is what you want. Secure the stem behind the eye with a few tight wraps of tying thread and then carefully snip the remainder of the stem off close. Sweep the fibers back with your fingertips and take wraps of tying thread all the way back to the base of the fibers.
I like the head and thorax of the fly to be fairly dark so I switch over to dark brown rabbit fur. A small pinch should be enough to create a thin short dubbing noodle on your tying thread. Starting just behind the eye, take wraps rearward to build up the dubbing and then wrap forward, taking wraps of bare thread behind the eye.
You can then do a 5 or 6 turn whip finish and snip or cut your tying thread free.
No, it's not a fancy looking fly and I can't imagine it having a lot of "bin" appeal in the fly shop but I can assure you, they're absolutely deadly on the river. They can be fished subsurface, say, behind a weighted nymph, but I really like them dropped off the back of a floaty dry, like a Goddard Caddis. This butter-belly fell for a size 18 in tan. As they say, elephants eat peanuts.