BOOKWORMS BACK 371 



pages together, thus causing the pages to fall apart (pi. 6). From 

 these original points of attack the grubs, as thej^ get more mature and 

 voracious, extend their tunnels through covers and pages, according 

 to the habit of the particular species, and so line their tunnels and 

 pupal chambers with a gluelike secretion that badly affected books may 

 literally become solid blocks of paper, to be opened only by main 

 strength, and then not without ripping and rending the pages into 

 worthlessness. Even a page as moderately damaged as that shown 

 in plate 8 can be separated from the next page only with care. Some 

 books (pi. 16) must be soaked in clear gasoline before any further 

 attempt is made to recondition their pages. 



Fortunately the bookworms most commonly attacking sheepskin 

 and cloth-bound books in law libraries and other collections through- 

 out the United States confine their ravages to the leather and the card- 

 board of the cover (pi. 15) and seldom burrow into more than a few 

 of the pages closest to the cover. When a number of the grubs are 

 burrowing in leather-bound books left for months without being re- 

 moved from the shelving, they will push out, from the holes they make 

 in the leather, chewed particles which fall and lie in small heaps on the 

 shelving between the exposed book ends. The excrement of bookworm 

 grubs gathers in their tumiels and between the pages as a fine dust 

 that may be as varied in its color as the differences in the type of paper 

 or the printing ruined by their feeding. From badly damaged books 

 this powder or dust will sift out when the book is shaken over paper 

 and can sometimes be collected by the quart. In plate 12 is shown the 

 well-grown white grub of a typical bookworm surrounded by the dust 

 it has formed as it has eaten out a cavity along the edges of the pages 

 where these are sewed together. All real destruction is caused by the 

 dust-making grubs. The adult beetles which mature close beneath 

 the cover or the edge of the pages escape from the book by eating 

 small round holes as shown in plates 1, 14, 16. The adults must reach 

 the exterior to mate, and they lay their eggs about the covers and 

 edges of the pages. 



The insects known as surface feeders are the common household 

 pests — cockroaches, silverfish, and psocids or book-lice. Although 

 psocids are very frequently seen running over books in some libraries 

 and in many homes and have been called lice because they are whitish, 

 tiny creatures, hardly as large as the head of an ordinary pin, their 

 importance as book pests has been exaggerated. They are frail 

 creatures that today are considered incapable of causing physical in- 

 jury to book covers. Since they do not bite people, carry disease, or 

 harm books, they are objectionable only in the annoyance they may 

 cause nervous persons who do not know that they are harmless. 

 Warmth and dampness favor their increase. 



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