By an exudation

George Graves, The Naturalist’s Pocket-Book, Londres, W. & S. Graves, 1817.

The individuals of this genus bear a considerable resemblance in their adult state, to some of the Phalenae, but are distinguishable by their not possessing the spiral tongue : the Larva is six-footed, and resides at the bottom of shallow waters, in a case, composed of small pieces of straws, whichare glued together by an exudation from the insect, the case is tubular ; lined with silk-like filaments, and is open at each end ; they feed on aquatic insects, the spawn of fishes, as also on the young fry.