My favorite caddis for Washington lakes is the Traveling sedge (Banksiola). They are big (size 9 or 10). They run along the surface of the water after they emerge (hence their common name). And trout will make slashing, leaping takes at them. My favorite pattern to imitate them is the Mikulak Sedge (do a search for a pattern), which is simple and effective.
Looks like a small dark caddis is in order. I'm familiar with the "traveling sedge" from a distance, but not up close. Looks like green pupa and olive adult (body) seems to be the most common color?
I recently had a conversation with someone about lake caddis in a particular lake and the time of year and so on, and I got a little curious. I'm trying to add some general patterns (not going to carry an entire caddis box!) and a little more knowledge about them and what to expect, where to look, and so on. Thanks for the replies.
Here's a pic of a Mikulak Sedge, as I tie it. I tie them in olive, burnt orange, and a bright green for bodies. I've used them successfully when dragon flies are egg laying and fish are trying to capture them on the surface.
Also, one key element in this pattern that doesn't display well in this side view is the oversized hackle that is clipped flush on top and bottom, but which sticks out quite far on the sides and helps create the sense of motion on the water. I will often fish these in fast strips, although sometimes just dropping them among lily pads and twitching them works great.
This reminded me of a day this past spring/summer. I was fishing a lake where a black caddis hatch was going off. I tried everything I had and was only catching the odd fish here and there. For whatever reason I tied on a Doc S. I have never caught a fish on this fly as far as I can remember so I'm not certain what inspired me to put it on. Anyway, as you can probably guess.... I started trolling this thing across the lake to reposition myself and almost immediately got a hook up. This continued for about an hour at which point my fly was torn to pieces and I hadn't made across the lake yet. When they quit hitting the tattered fly I put a new one on. However, the excitement was over. Anyway, it wasn't until later at home when I was thumbing through my fly books that I realized the link between those caddis and the Doc Spratley. I'm going to make a trip to that lake again about the same time this year and see if there can't be a repeat performance. Oh, I talked to another gentleman that had similar success with a Half Back during that hatch.