The Serendipity is both a midge and a caddis pupa imitation. It can be tied using a wide variety of materials for both the body and the wing bud, but this is how I like to tie a Serendipity. For me, small sizes of this pattern work better than larger ones, so I tie them small, here I'm going to use a size 20 Dai-Riki #125 Emerger hook.
Begin by mashing the barb on the hook as flies this small can be tricky to remove, and then get your hook set firmly in the vise.
For thread, I'm going to go with Uni-thread 8/0 in red. Start your thread on the hook shank leaving a little space behind the eye and then snip the tag off close.
Although many other materials will work for the body of the fly, a stripped saddle hackle feather is one of my favorites. Leave a few fibers at the butt and tip for easier handling. Secure the tip end of the stem to the hook shank and begin taking thread wraps rearward down into the bend and then back up the shank to the tie-in point. You can then break or snip the tip end off.
To increase the fly's durability use your bodkin to scoop up just the smallest amount of Zap-a-Gap and apply a very light coat to the thread wraps. Get hold of the stem and begin making adjacent wraps up the hook shank. With a little practice, you'll be able to make the body taper a bit by including the thicker part of the stem. At the tie-in point, secure it with a few tight wraps of tying thread. You can then snip it off close.
For the emerging wings, snip a small clump of deer body hair free from the hide. How much deer hair really depends on it's thickness and the size of the fly. I'm guessing I've got about 20 fibers here. While firmly holding the bundle, snip off the tips at a right angle and keep squeezing the bundle. Place it on top of the hook, right at the eye, and take a loop of thread. While still squeezing the bundle, pull the thread loop tight. Continue to take tight wraps to further secure the bundle and cover up the deer hair butts. Lift the remaining deer hair up just a bit and snip it to form wings about half a hook shank in length. You can then do a 4 or 5 turn whip finish and snip or cut your tying thread free.
A small drop of head cement applied to the wraps will make sure everything stays where it belongs. And that's the Serendipity. Fished subsurface or in the film, it's one of those patterns that has proven itself to work just about anywhere and throughout the year.