Flotation

 

George J. Romanes, Animal Intelligence, Londres, Kegan Paul, Trench, 1882, p. 240

Only two other instances of noteworthy intelligence as exhibited by larvae have fallen within my reading. One of these is mentionned by Réaumur, who says that the larvae of Hemerobius chrysops chase aphides, and having killed them, clothe themselves in their skins ; and the other case is the very remarkable one mentioned in his newly published work by W. MacLahlan, F.R.S., of caddis-worms adjusting the specific gravity of their tubes to suit that of the water in which they live, by attaching heavy or light material to them according as they require sinking or flotation.