Chapter Buddha to Bug of B by Webster's Dictionary (1913 Edition)

5. (Zoöl.) One of certain kinds of Crustacea; as, the sow bug; pill bug; bait bug; salve bug, etc.

According to present popular usage in England, and among housekeepers in America, bug, when not joined with some qualifying word, is used specifically for bedbug. As a general term it is used very loosely in America, and was formerly used still more loosely in England. "God's rare workmanship in the ant, the poorest bug that creeps." Rogers "This bug with gilded wings." Pope.

Bait bug. See under Bait. — Bug word, swaggering or threatening language. [Obs.] Beau. & Fl.