Thomas Miller, English Country Life consisting of Description of Rural Habits, Country Scenery and the Seasons, Londres, Routledge, Warnes, 1859, p. 203-204.
When the streams are low through the summer droughts, many curious insects may be seen in the water, which would escape the eye when the runnels are swollen with the rains of Winter and Spring. Some of these curious habitations of stones, shells, hollow seeds, straws, even mud and small particles of wood, which they cement together, forming a vaulted roof, or pent-house, over their heads, and with their building on their backs they move about in the little world for which Nature has adapted them, accomplish the ends for which they were created, and then die Amongst these stand foremost the caddis-worms, which compose the little cube-like cells they inhabit, out of stones, with all kinds of irregular angles, and such as would baffle the skill of any human architect to fasten together. Yet, all this is done by the little caddis-worm.
The smooth side of every stone is placed in the interior, and the whole mass secured together by a cement which the water has not the power to dissolve . Even the portion of the body of the worm which is exposed, is hard and firm, while that part which the cell covers is soft ; for so has Nature defend this curious insect. To an unpractised eye, the whole of this wonderful structure would present only the appearance of a piece of reed or straw, which the water had discoloured ; while the naturalist would find in it the little insect, and a perfect habitation formed of many a loose rough particle, as our engraving shows, but which is so smooth and even at the bottom, that the architect can move about with its house upon its back with case.