Page:Popular Science Monthly Volume 55.djvu/255

Rh in the search for specimens of the "destroyer," many of them revealing the fact that some unique and curious creature which stands alone in its taste for literary food was sought. Mr. Blades reported in 1858 that he found specimens in some black-letter fragments at the Bodleian Library, that were recognized by the librarian. Dr. Bandinel, who crushed them with his thumb, saying, as he wiped his thumb nail on his coat sleeve, "O yes, they have black heads sometimes." The librarian of Hereford Cathedral, the Rev. F. S. Havergal, contributes his observations, covering a period of eighteen years, during which time he reports that he found two distinct species. From his description, however, it appears that he failed to recognize that the two were the larva and imago of the same species. Many cases of the finding of bookworms reported in England and America are not accompanied with sufficient data to determine just what they were. These contribute to the general impression that many have sought but few have found what were thought to be "genuine bookworms," while on every hand are those creatures which under the right conditions become book destroyers.

Research among the literature concerning library pests reveals the fact that no less than eleven different groups have members that are directly or indirectly accused of injuring books and bindings. The number of species in each group ranges from one to eleven, making a total of over thirty different species. In addition to these there are others against which the evidence is at best only circumstantial. It is not necessary to say that none of these bear any resemblance in any period of their existence to worms, and that the term bookworms is a misnomer. The word has become so firmly fixed in literature, both in its figurative and literal sense, that its misuse will no doubt continue.

The larger number of these are included in the class Hexapoda, or insects. Two species belong to the class Arachnida, which embraces the scorpions, spiders, mites, etc. One of these, Chelifer cancroides, known as the "book scorpion," although not a true scorpion, belongs to the order Pseudoscorpiones, and is probably what Aristotle had in mind when speaking of the "little scorpionlike insects found in books." The other species is known as Cheyletus eruditus, of the order Acarina, or "cheese mites." These two are known to be carnivorous in their habits, and there is some question as to whether they haunt books for the purpose of feeding on them or on other creatures to be found there.

Of those in the class Hexapoda, which comprises all the other known book pests, there can be no question as regards their destructiveness. Many are known about the house by the name of the article they are most frequently found in, and unless driven by a