STONE AND WOOD BORERS 



353 



persistent strokes like the ticking of a watch. Another 

 insect, called the book-louse (Atropos divinatoria), very 

 minute, only one-twentieth of an inch, soft, white, and 

 wingless, not a beetle at all, but also a devourer of 

 literature (Fig. 64), is declared by some good observers to 

 be a " ticker " or " tapper," but other naturalists deny that 

 it can make such sounds. It seems unlikely on account 

 of the extremely small size and 

 softness of the book-louse, but 

 the matter needs further investi- 

 gation. 



A curious fact is that the 

 grubs of beetles such zsAnobium 

 and Xestobium (or other closely 

 allied kinds) are not arrested in 

 their tunnelling by soft metal. 

 They cannot tackle iron plate 

 or brass sheeting, but they will 

 penetrate tinfoil and, what is 

 more astonishing, lead plate and 

 leaden waterpipes. Specimens 

 showing such perforations are in FIG. 63. The silver-fish insect 



the museums of Oxford and (Lepisma saccharina). The 

 T j j T i j li ne to the right shows its 



London, and I have received an natura i size 

 account of a lead pipe packed in 



wood in the wall of a house being perforated by these 

 beetle-grubs. Once at work on the wood, " the straight- 

 forward intentions " of the grub are not to be diverted by 

 such an obstacle as lead : it goes straight on through the 

 lead as it would through the cover of a book or a knot 

 in the wood. 



I have sometimes been asked to give advice as to the 



best method of destroying the furniture worm or grub. 



If the piece of furniture (or its pieces) can without injury 



be " baked " in a hot chamber for twenty-four hours, at a 



23 



