Page:Popular Science Monthly Volume 55.djvu/257

Rh the most important, perhaps, being that of the Natural History Museum Reports, at Albany, where Mr. J. A. Lintner found a hundred volumes or more so badly damaged by roaches that they could not be moved without coming to pieces. The United States Senate Reports, bound in cloth and leather, some fresh and new, have been badly damaged at Washington, in the efforts of these pests to get at the paste with which the covers were fastened to the volumes. The species known to commit these depredations are the "Croton bug" (Blatta germanica), smaller than the others, but considered by some writers as the worst pests of the family; a little larger species, called Periplaneta orientalis; and a large species, known as Periplaneta americana, or Kakerlac. Against two other species, Blatta australasiæ and Blatta gigantea, there is not so much evidence.

Among the moths, or millers, order Lepidoptera, are found several species which injure books, the best known being the Aglossa pinguinalis, commonly called "grease moth." The larva of this species is at first a pale, flesh-colored grub, but as it matures it becomes quite black. It injures bindings by constructing long "silken tubes," in which it remains until full fed. Sometimes they spin a web between the volumes, "gnawing small portions of the paper with which to form their cocoons." This species belongs to the family Pyralididæ. Of the family Œcophoridæ two species are known to injure books: Acompsia pseudospretella, and an undetermined species of Depressaria. Under the name Œcophora, William Blades describes the ravages of the former on two leaves of a "Caxton," and accompanies his remarks with a photographic illustration of the damaged leaves, from which it is at once seen how irregular is the gnawing of this species. The newspaper account of the finding of bookworms in the Lenox Library not long ago classed the larvæ found with this species.

The largest number of book-destroying insects are found among the beetles, of the order Coleoptera. To this group belong the "book borers." The species thus far considered have been more or less dilettants in literature. The beetles, however, seem possessed with a true spirit of investigation, and when they undertake a piece of work in a serious fashion they go to the bottom of it, sticking close to the line laid down. This characteristic distinguishes these insects from all others, and makes it comparatively easy to determine when they have been at work in a worm-eaten volume. No less than sixteen different species of this order have been either detected in this work, or such strong circumstantial evidence has been found against them, that there is little doubt as to their guilt. Some insects seem to destroy books for the sheer want of something better to do; some do so in seeking the paste and sizing used in and about the books; others