Evangeline Bradhurst, « Shells in our Rivers and Ditches », The Essex Review, Colchester, vol. XVII, n°65, janvier 1908, p. 90.
The number of tiny shells the caddis fly envelope collects is a museum of study in itself. In my caddis fly’s discarded home, on the empty tube. I count the shells of Bithynia leachii, Valvata piscinalis, Valvata cristata and Sphaerium corneum, all so small that the whole collection would easily rest on a threepenny bit !