Theodore Wood, Practical Lesson on Insect Life, Londres, Joseph Hughes, 1882, p.104-105.

Unlike those insecs, however, they construct for themselves habitations, or « cases » in which to pass their larval existence, these differing in structure according to the species of the insect, and the nature of its surroundings. As a rule, these cases are more or less cylindrical and are formed of all manner of substances, leaves, sans, small stones, sticks, etc., being amongst those usually employed. The grub is however, by no means particular in its choice, and will make use of any suitable object which may fall in its way.