Harold Bastin, « Maskend Insects », The Pageant of Nature, Volume III, Londres, Édité par P. Chalmers Mitchell, The Waverley Book Company, circa 1910.
The most noteworthly subaquatic case-makers are the caddis-worms, of which almost any ditch, pond or stream will supply numerous examples. Their cases, or sheaths, are familiar objects; but comparatively few people know what a caddis-worm really looks like because these insects objects strongly to leave their homes. Forcee and persuasion applied through the front door prove alike futile. The larva simply refuses to budge! …./……If we drop a few naked caddis-worm into a small aquarium – say a 2 lb. glass jam jar- and supply them with building materials, we shall soon witness a demonstration of their craft.
They are very active and seem animated by one desire, namely, to make fresh homes for themselves with as little delay as possible. They will utilize almost any objects of suitable size which may be given to them- beads, small pieces of coloured glass, china or metal, or shreds of cloth.
But in normal circumstances each species evinces a characteristic conservatism, and builds only with materials that its ancestors have used before it, following also a time-honoured plan. Thus, while some of the cases are of tiny stones, or of mixed stones and shells (often with their living inmates) others are of small pieces of leaf or grass, in one instance arranged lengthwise, in another obliquely. For contrast with these neat productions, there are flattish and irregular cases loosely made of large bits cut by the larvae from leaves which have fallen into the water; while some species after constructing a cylinder of sand grains, invarriably mar its symmmetry by adding long pieces of twig or reed-probably as Réaumur suggested, for the purpose of adjusting the specific gravity of the case to that of the water in which it is immersed.