Irene Finch, Pond Animals, Londres, Longmans, 1969, p. 46.
Swimming Caddis larva
This looks like a green stick, movig slowly and steadily, using two long legs to swim. There are four oyher shorter legs as well. If you find a big case and look carefully you will see that it is made of pieces of weed cut very evenly and arranged in a regular spiral. These larvae pupate like other caddis but I am not sure if they eat weed.