E. Marshall-Hardy, Anglers Ways, Londres, Herbert Jenkins, 1960, p. 62.

These grubs build round themselves a case or tibe of sand and tiny stones which forms their home and protection. Lying on the river bottom or under stones in the shallows, they look exactly like small pieces of stick or twig. When carefully stripped of this case they have the appearance of splendid gentles, and are used in thesame way.