Richard Bowlker,  The Art of Angling or Complete fly & bottom-fisher, Londres, H. Procter Ludlow, 1814, p. 125.

He continues on the water till about the beginning of July; he is bred from the cod-bait, a curious little creature. While in the state of a grub, he is greatly to be admired, the outside husk he lives in being curiously wrought with gravel or sand.