Robert Williamson from “Soul of Streams” has a great little piece on rock rollers
(aka rock worms, aka cased caddisflies). Robert is an excellent fly tier here in Utah, specializing in air-filled and chain-stitched flies. He first had this current piece on his blog published in Fly Fishing & Tying Journal
(in other words, this guy is legit when it comes to writing and tying—not a hack like some of us). He has some nice science and history in the post. Go check it out.