Beneath the stones

Kathleen E. Carpenter, Life in inland waters with especial reference to animals, Londres, Sidgwick & Jackson, 1928, p. 141.

Beneath the stones, and in their crevices, some larger caddisses than those of the moss are to be found, delicate types with weak, soft cases would be in danger here, in the grinding of the pebbles, and those which flourish are especially Agapetus, Stenophylax, and Apatania, which make firm, well-built cases of small pebbles.