cod-worm

May-fly, which is bred of the cod-worm or caddis; and these make the trout bold and lusty, and he is usually fatter and better meat at the end of that month (May) than at any time of the year.

The Best of the World's Classics, Restricted to prose. Volume III (of X) - Great Britain and Ireland I Various 1885

He will bite at a paste made of brown bread and honey, or at a Marsh-worm, or a lob-worm; he inclines very much to any paste with which tar is mixt, and he will bite also at a smaller worm with his head nipped off, and a cod-worm put on the hook before that worm.

The Compleat Angler : or, The Contemplative Man`s Recreation 1653

Nay, sometimes a worm, or any kind of fly, as the ant-fly, the flesh-fly, or wall-fly; or the dor or beetle which you may find under cow-dung; or a bob which you will find in the same place, and in time will be a beetle; it is a short white worm, like to and bigger than a gentle; or a cod-worm; or a case-worm; any of these will do very well to fish in such a manner.

The Compleat Angler : or, The Contemplative Man`s Recreation 1653