Enid Blyton, Nature Lover’s Book, Londres, Evan Brothers, 1944, p. 52.

« Muff-like in shape, » said Uncle. « Perhaps one day you will see one-you certainly would if you kept a pair of sticklebacks in an aquarium, and gave them bits and pieces to build a nest. Now I just want to show you the little creature I told you about that builds itself a house. »
Uncle Merry scraped about in the mud in a certain place in the pond- and brought up two curious creatures. He showed them to the children. It looked as if he was holding two tubes made of bits of stick and tiny grains.
« The little insect that lives inside theses cases has a very soft body that other ponds-animals like to eat, » he said; « so, to protect himself, he gathers together ay odd bits and pieces he can find in the water, glues them together, and makes himself this funny little house. There he lives quite safety, putting out his head and legs when he wants to crawl about, and able to hide himself quickly when ennemies swim near. »
« Do these funny little grubs turn into anything? » asked Janet.
« They are caddis grub, the grub of the caddis fly, » said Uncle Merry. « There will come a day when they crawl from the water, and fly away into the air, complete with wings. »
The curious « houses » were returned to the pond, and the children spent some time in watching the water-snails on the weed, and some big black beetles coming up to the surface of the pond for air. The water was full of life, and the ramblers spent a whole hour watching the creatures that made it their home.