He was transparent, like thin ivory, and had a dark line through his body, which I took to be the intestinal canal.

He resigned his life with extreme procrastination, and died "deeply lamented" by his keeper, who had long looked forward to his final development.
The difficulty of breeding these worms is probably due to their formation.

When in a state of nature they can by expansion and contraction of the body working upon the sides of their holes, push their horny jaws against the opposing mass of paper.

But when freed from the restraint, which indeed to them is life, they CANNOT eat although surrounded with food, for they have no legs to keep them steady, and their natural, leverage is wanting.
Considering the numerous old books contained in the British Museum, the Library there is wonderfully free from the worm.

Mr.Rye, lately the Keeper of the Printed Books there, writes me "Two or three were discovered in my time, but they were weakly creatures.