\In*du"sial\, a. [See {Indusium}.]
Of, pertaining to, or containing, the petrified cases of the
larv[ae] of certain insects.

{Indusial limestone} (Geol.), a fresh-water limestone,
   largely composed of the agglomerated cases of caddice
   worms, or larv[ae] of caddice flies ({Phryganea}). It is
   found in Miocene strata of Auvergne, France, and some
   other localities.