In a short time

J. E. Roberts, A year with nature, Londres, Edward Arnold, 1951, p. 102.

The caddis fly is somewhat like a moth and is brown in colour. The white larva lives at the bottom of streams and ponds and builds a little home of tiny shells ans stones to protect itself. The head and legs protrude and it is able to walk about in this suit of armour. April is a good month to search for them, and if you take one carefully out of its case and place it in clean water and provide it with materials it will make a new case in a short time.