1911 Encyclopædia Britannica/Death-watch

DEATH-WATCH, a popular name applied to insects of two distinct families, which burrow and live in old furniture and produce the mysterious “ticking” vulgarly supposed to foretell the death of some inmate of the house. The best known, because the largest, is a small beetle, Anobium striattum, belonging to the family Ptinidae. The “ticking,” in reality a sexual call, like the chirp of a grasshopper, is produced by the beetle rapidly striking its head against the hard and dry woodwork. In the case of the smaller death-watches, some of the so-called book-lice of the family Psocidae, the exact way in which the sound is caused has not been satisfactorily explained. Indeed the ability of such small and soft insects to give rise to audible sounds has been seriously doubted; but it is impossible to ignore the positive evidence on the point. The names Atropos divinatoria and Clothilla pulsatoria, given to two of the commoner forms, bear witness both to a belief in a causal connexion between these insects and the ticking, and to the superstition regarding the fateful significance of the sound.