Eric Parker, Fine angling for Coarse Fish, Londres, Service & Co., Seeley, 1930, p.57.

.. in hot weather roach are sometimes finicky feeders, but even under such conditions they will often fall to a caddis grub which is know, too, as a case-worm or stick-bait. These grubs have all the appearance of very luscious gentles and areto be found in ditches or in the shallower parts of the river. Most of them live in and build for themselves small cases of sand and other detritus, which look for all thye world like small dead pieces of stick lying at the bottom. To these are attached small stones which serve to make the whole of them heavier than water. The cases which they build and which form their protection are marvels of ingenuity some being encrusted with tiny stones. It is possible to buy caddis grubs by the pint. Otherwise, boys are very helpful when a supply is wanted…