Xylophaga. This is the name of both a genus of Mollusca and a section of Beetles. In the former it is used for a member of the class Lamellibranchiata (q.v.), which bores into wood floating in or submerged beneath the sea. It is closely allied to the genus Pholas, which bores into soft limestone and hard clays. The section of Beetles for which it is employed includes the Boring Beetles or Bark Beetles, which are very destructive to trees; thus Scolytus destructor (Oliv.) lives in the elm, Phloeotribus oleoe (Fabr.) in the olive.