David Sharp, Insects, Londres, MacMillan, 1895, p. 474 et 476.

The habitations constructed by the larvae are, many of them, of a curious nature, and usually attract more attention than do the creatures they serve to protect.

As soon as the larvae are hatched they begin to provide themselves with cases ; they select small pieces of such material as may be at hand in the water, and connect them together by means of silk spun from the mouth. Particulars as to these tubes we will defer till we have considered the larvae themselves.