John J. Brown, The American Angler’s Guide; or complete Fisher’s Manual for the United States, New York, D. Appleton & Co., 1857, p. 36-37.
The Cadis, or Cad-bait, and Straw-Worm, are found in the shallow, sandy parts of rivers, small broks, and even ditches. The first is a yellowish grub, with a reddish bead, and is covered with a case or husk of straw, bark, bits of rushes, particles of gravel, &., and with this covering to shelter it, is enabled, by protruding its head, to creep on the bottom of the stream where it is found. There is another similar kind, of several varieties, called the straw-worm, with produce different sorts of flies. They are all excedent bait for trout.