The creature that live inside

George E. HydeA Pocket-Book of British Insects, Londres, Adam & Charles Black, 1949, p. 118.

Anyone who has hunted for tadpoles and other ponds animals must have noticed various tube-like structures, composed of small stones, bits of twig and general debris, in the water. These are the shelters or dwelling of Caddis-fly larvae, and although their composition varies considerably, their purpose remains unchanged. The creatures that live inside the narrow walls of these strange quarters are soft-bodies except in the forepart and head, and they move about the pond bottom and amongst the water weeds on six legs, which are withdrawn into the shelters when not in use.