(1) Not so! Several correspondents have drawn my attention to the
fact that Hooke is evidently describing the "Lepisma," which, if not
positively injurious, is often found in the warm places of old houses,
especially if a little damp. He mistook this for the Bookworm.
Entomologists even do not appear to have paid much attention to the natural history of the "Worm." Kirby, speaking of it, says, "the larvae of Crambus pinguinalis spins a robe which it covers with its own excrement, and does no little injury." Again, "I have often observed the caterpillar of a little moth that takes its station in damp old books, and there commits great ravages, and many a black-letter rarity, which in these days of bibliomania would have been valued at its weight in gold, has been snatched by these devastators," etc., etc.
As already quoted, Doraston's description is very vague. To him he is in one verse "a sort of busy worm," and in another "a puny rankling reptile." Hannett, in his work on book-binding, gives "Aglossa pinguinalis" as the real name, and Mrs. Gatty, in her Parables, christens it "Hypothenemus cruditus."
The, Rev. F. T. Havergal, who many years ago had much trouble with bookworms in the Cathedral Library of Hereford, says they are a kind of death-watch, with a "hard outer skin, and are dark brown," another sort "having white bodies with brown spots on their heads." Mr. Holme, in "Notes and Queries" for 1870, states that the "Anobium paniceum" has done considerable injury to the Arabic manuscripts brought from Cairo, by Burckhardt, and now in the University Library, Cambridge. Other writers say "Acarus eruditus" or "Anobium pertinax" are the correct scientific names.
Personally, I have come across but few specimens; nevertheless, from what I have been told by librarians, and judging from analogy, I imagine the following to be about the truth:—
There are several kinds of caterpillar and grub, which eat into books, those with legs are the larvae of moths; those without legs, or rather with rudimentary legs, are grubs and turn to beetles.
It is not known whether any species of caterpillar or grub can live generation after generation upon books alone, but several sorts of wood-borers, and others which live upon vegetable refuse, will attack paper, especially if attracted in the first place by the real wooden boards in which it was the custom of the old book-binders to clothe their volumes. In this belief, some country librarians object to opening the library windows lest the enemy should fly in from the neighbouring woods, and rear a brood of worms. Anyone, indeed, who has seen a hole in a filbert, or a piece of wood riddled by dry rot, will recognize a similarity of appearance in the channels made by these insect enemies.
Among the paper-eating species are:—
1. The "Anobium." Of this beetle there are varieties, viz.: "A. pertinax," "A. eruditus," and "A. paniceum." In the larval state they are grubs, just like those found, in nuts; in this stage they are too much alike to be distinguished from one another. They feed on old dry wood, and often infest bookcases and shelves. They eat the wooden boards of old books, and so pass into the paper where they make long holes quite round, except when they work in a slanting direction, when the holes appear to be oblong. They will thus pierce through several volumes in succession, Peignot, the well-known bibliographer, having found 27 volumes so pierced in a straight line by one worm, a miracle of gluttony, the story of which, for myself, I receive "cum grano salis." After a certain time the larva changes into a pupa, and then emerges as a small brown beetle.
2. "Oecophora."—This larva is similar in size to that of Anobium, but can be distinguished at once by having legs. It is a caterpillar, with six legs upon its thorax and eight sucker-like protuberances on its body, like a silk-worm. It changes into a chrysalis, and then assumes its perfect shape as a small brown moth. The species that attacks books is the OEcophora pseudospretella. It loves damp and warmth, and eats any fibrous material. This caterpillar is quite unlike any garden species, and, excepting the legs, is very similar in appearance and size to the Anobium. It is about half-inch long, with a horny head and strong jaws. To printers' ink or writing ink he appears to have no great dislike, though I imagine that the former often disagrees with his health, unless he is very robust, as in books where the print is pierced a majority of the worm-holes I have seen are too short in extent to have provided food enough for the development of the grub. But, although the ink may be unwholesome, many grubs survive, and, eating day and night in silence and darkness, work out their destiny leaving, according to the strength of their constitutions, a longer or shorter tunnel in the volume.