Considering the fact that Pliny is said to have comprised in his Natural History all the knowledge of the natural sciences then known, it is a little surprising that he had not more to say regarding book insects. Here and there in his writings, however, he speaks of worms in connection with books and papers in the same casual way as other classical writers, causing you to feel that he was conversant with their destructive tendencies. The epigrammatist Martial in the first century, and Lucian in the second, both use the term bookworm; Martial, in much the same way as did Horace, warning his book of the fate awaiting it; Lucian, in his well-known dialogue, The Dream; or, The Cock, as a symbol of the condition to which miserly man may descend.
Sufficient has been said to show the attitude of the ancients toward these little pests, that had no more regard for their precious thoughts than for the utterances of modern "statesmen," whose speeches are "read by title and ordered printed."
Crossing the cloistered period of the ages called dark, when books were so few and so constantly used by the jolly monks that these little creatures must have had a difficult time getting a living unobserved, we come down to the sixteenth century, by which time books had begun to multiply and worms to propagate. In the last quarter of this century we find Pierre Petit, who is numbered among the celebrated pleiade of Latin verse writers along with Rapin, Commire, and others, addressing these "impudent creatures" in a thirty-four-line Latin poem titled In Blattam.
A curious and interesting characterization of some species of book insects has come to us in the writings of Christian Mentzel, the German naturalist and philologist, who lived in the seventeenth century. When one reads that he heard the bookworm crow like a cock, and said, "I knew not whether some local fowl was clamoring or whether there was but a beating in my ears," one can not help wondering if there was not something defective in his ear drums; but further on he says, "I perceived, in the paper whereon I was writing, a little insect that ceased not to carol like very chanticleer, until taking a magnifying glass I assiduously observed him." From this one concludes that if the fault were not with his hearing, by which some well-known sounds made by book insects seemed to him like the crowing of a cock, an altogether different cock from the kind we know must have lived in his day.
The earliest observations on the subject possessing any scientific value were made by Robert Hooke in his Micrographia, published in London in 1665. In many respects this work was a curious medley of facts and fancy. The registers of the Royal Society, of which he was a member, testify to the eagerness with which Hooke hurried from one inquiry to another with "brilliant but inconclusive results." Among the many objects which engaged his attention was an insect which he described in a chapter entitled Of the Small Silver-colour'd Bookworm. His description shows it to have been the "fishtail," by naturalists called Lepisma, well known as one of the pests that not infrequently is found in the library as well as other parts of the house.
Many interesting instances of the discovery of bookworms are found in the literature on the subject, showing the keen interest felt 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 lack of those things more to their liking, they do not invade the literary sanctum. Some are so cosmopolitan in their tastes that they seem to take whatever is most convenient, whether it be books or boots, pepper or poison.
As has been said, the earliest observation of value was made by Hooke on Lepisma, commonly known as "fish moth" or "silver fish," from its resemblance, in shape and coating, to a fish; also as "bristle tail," from its caudal appendages. They are found in closets, cupboards, and clothes baskets. Opinions have differed as to its destructiveness to books, but the weight of evidence is against the insect. It seeks the paste and sizing used about books, and this leads it to attack bindings and labels. There is a theory that paste made from pure starch is not to their liking, but this is not substantiated by observation.