Edward Burnham, « The Home of the Black-Fly », Manchester Institute of Arts and Science, Manchester, vol. IV, 1904, p. 83.
Under the stones are the sprawling nymphs of the stone-flies, which seem never to be doing anything or to have anything to do; while in the brook-weed are countless larvae of the caddis-flies-some in cylindrical stone cases that can be moved about; some in little house made of grains of sand, fastened together and to a stone with silk; some in tubes of silk and sand, with a net of silk near the mouth, with serves as a trap to catch whatever the swiftly running water may bring along.