What is "pill wood louse"

Pill \Pill\, n. [F. pilute, L. pilula a pill, little ball, dim. of L. pila a ball. Cf. Piles.]

1. A medicine in the form of a little ball, or small round mass, to be swallowed whole.

2. Figuratively, something offensive or nauseous which must be accepted or endured.
   --Udall.

   Pill beetle (Zo["o]l.), any small beetle of the genus Byrrhus, having a rounded body, with the head concealed beneath the thorax.

   Pill bug (Zo["o]l.), any terrestrial isopod of the genus Armadillo, having the habit of rolling itself into a ball when disturbed. Called also pill wood louse.