This pattern is similar to the Brassie, but the incorporation of a wire body plus a bead head makes the fly very dense for its size so it gets down in a hurry.
Hook: Scud, size 12-18 (here, a size 14)
Head: Bead head, size to match hook
Thread: Olive, 6/0
Abdomen: Fine wire (copper, nickel, etc.)
Thorax: A few turns of peacock herl