A Monsieur Rollin lately exhibited before the French Academy, a silkworm's cocoon of a rose color; remarkable because the color was produced by feeding the worms upon mulberry leaves sprinkled with chico (Bigo-nia chica.) A cocoon had been exhibited on a former occasion of a blue tint, produced by sprinkling indigo upon the mulberry leaves-The tint in the present case was, however, much stronger than that of the blue cocoon.