Chapter 44
Chapter 42 of House, Garden, and Field by L. C. Meal. This LibriVox recording is in the public domain. Furniture beetles, bookworms, and death watches. In the days of timber-built houses, much loss was caused by the borings of small beetles, which riddled the beams, floors, and wainscots, and often spoiled the furniture as well. Now that we build with brick and plaster and paint-exposed surfaces of wood, the ravages of these insects have been lessened to such a degree that few
houses contain the worm-eaten timber, which was formerly so common and so vexatious. An attack of furniture beetles is indicated by round holes in the wood and little heaps of fine dust thrown out from them. The round holes lead to cylindrical burrows, which may run far beneath the surface, and in bad cases the strength of the wood is impaired. The hardest and driest wood is not safe, for bootlaths and the legs of chairs, daily warmed before a fire, have been attacked.
It is the larva of the beetle which does the mischief. This is a whitish, soft-bodied grub, whose body is curved like that of a cockchafer larva. Its head, jaws, and small legs are the only hard parts, and also the only parts which show a distinct color. Observation of other insects might enable us to predict that the growth of any larva which feeds upon dry wood will be slow. Hardly any poorer stuff for food can be found,
but the supply is inexhaustible and the larva runs no risks. A furniture beetle has been known to pass three years in the larval stage. Contrast this with the history of a leaf-eating larva. Here the food is both more nutritious and easier of digestion. The time during which it can be procured is limited to the warm season
and many enemies await the larva. Its best policy is to feed without intermission and get the dangerous growing period over as soon as possible. We have seen that the larval stage of a furniture beetle lasts three years, and subterranean root-eating larvae, such as wireworms,
may go on feeding as long or even longer. But the leaf-eating larva of the turnip beetle is full-fed in a week. When the end of its protracted feeding time grows near, the grub of the furniture beetle prolongs its burrow nearly to the surface of the wood, and here it is said, I cannot vouch for the fact,
to spin for itself a cocoon of silk interwoven with particles of wood. Then it pupates, and in due course the beetle emerges, the thin barrier of wood which was left as a protective covering to the burrow being easily broken down. The beetle is three or four millimeters, one-eighth to one-sixth of an inch long,
and of a dull brown color, varied on the sides of the body with grayish hairs. The head is bent downwards and sunk into the prothorax, which covers it like a hood. it does not appear when the insect is seen from above. The legs can be tucked under the body
so that it is a simple matter for the beetle, when alarmed, to sham dead, its rounded shape, inconspicuous color, and complete immobility, allowing it to pass for a mere pellet. The beetles often strike the wood of their galleries with their heads and so produce a ticking sound, which is a call to the mate.
The ticking is most frequent in the summer months, but in warmed rooms it may be heard at any time of the year. The commonest of our furniture beetles is called Anobium domesticum, or striatum. This is the beetle whose dimensions were given above. Another species, which is nearly twice as long, Anobium tessalatum, has very similar habits,
and is the beetle which has been most frequently heard to tick. In the dead of night, this ticking sound, distinct but inexplicable, strikes the mind with a vague terror, like the sudden cracks of dry timber or the dripping of unseen water, and what is really no more than the call of a minute beetle has come to be feared as a warning of death, hence the name of death watch given to the enobiums and some other insects which make a
noise like that of a watch. The late Frederick Smith of the British Museum tells us that, having received two live examples of enobium tessalatum from Mr. Doubleday with full instructions, he tapped the table several times in rapid succession with a lead pencil when the beetles raised themselves on their front legs and, bobbing their heads up and down, struck the bottom of the box in which they were kept with their mandibles. This performance he could set up almost at pleasure.
The number of the taps was usually four or five. In the state of nature, the furniture beetles excavate living or dead trees, usually running their galleries in the sapwood. Quote, Notwithstanding the obscurity and retirement of their life, these wood-boring beetles have not manage to escape the attacks of parasites. Several species of Ichnumen flies and other allied insects prey upon them, and the delicate little gauzy-winged persecutors may sometimes be
seen running about hither and thither over anobium-infested wood in maternal anxiety to find a suitable nidus for their brood. Some, too large to enter the burrows, are furnished with a long ovipositor with which to reach their victims, into whose bodies they insert their eggs. Others are small enough to enter the burrows bodily and hunt their prey like a ferret after a rabbit. One of these latter, Theocolax formisiformis, superficially something like a minute ant,
in consequence of the absence of wings, I have obtained inconsiderable numbers from a colony of Enobium domesticum, which had established themselves in an old aquarium stand." Unquote. From E. A. Butler, Our Household Insects, page 11, 1893. Enobium penicium, one of the furniture beetles is also the weevil which devours ship's biscuit. It attacks all sorts of vegetable substances, wood, paper, and drugs of various kinds. There is another furniture beetle which
now and then commits great ravages, especially in our southern counties. This is the Tillinus pectinicornis. It is of the size of a nobium domesticum and distinguished from it by the antennae, which are long and plumos in the male, shorter and simpler in the female. The grub of Phenobium domesticum is not only a devourer of wood, it eats paper as well, and is one of the so-called bookworms. Its burrows may extend from one neglected book to others on the same shelf,
and Peneaux has recorded an instance in which twenty-seven folio volumes placed side by side on the shelf were drilled through by one larva, so that a string might be run through the hole and all the volumes raised by the string. It is rare to find so straight a gallery as this, but we may often find torturous galleries several inches long. It is chiefly old books which are injured in this way.
The general use of chlorine bleach paper, though a cause of decay in other ways, and the substitution of cheaper materials for linen rags, have probably checked the ravages of bookworms. Several sorts of insects and a few animals of other classes deface or destroy books.
Furniture beetles bore into the covers, besides running their galleries through the piles of unreadable pages. Cockroaches nibble the binding, and now and then the edges of the leaves. Silverfish gnaw the binding, and leave characteristic sinuous tracks. When the paper has been printed, they leave untouched the inked parts,
so that a printed page becomes a tattered skeleton. A small mite, Chaletus erudis, has sometimes been found in numbers among books which have been stowed away in damp places, but it is really of carnivorous taste, and feeds not on the paper, but on the small creatures which lurk in the books. A chellifer, which might be briefly described as a minute, tailless scorpion, is also found
among neglected books, where it pursues its prey. So many insects attack large collections of books, and so great is the damage done by them, that it is part of the professional education of the librarian to know the marks by which the different kinds are recognized, and the methods of extermination appropriate to each.
Fifty or sixty book-destroying insects and mites have been catalogued, and books have been written to describe them and explain how they are to be combated. Blades on the Enemies of Books is a well-known English treatise. The latest study of bookworms is Dr. Hulbert's Insects Enemies de Livre, Paris, 1903. Just as there are several different kinds of bookworms, there are several different kinds of death watches. Small insects, atropis, belonging to
the family of Sosidae and believed to be allied to white ants, make a ticking very like that of synobium. Two species of atropis are common in our houses, frequenting dusty recesses, neglected straw, old papers, picture frames, etc. They are often found on wallpaper. Both are so small as to require a lens to identify them. One kind, A. divinatoria, can be recognized by the vestiges of wings, which project as scales from the middle of the thorax. It has larger eyes than the other
species, its length does not exceed one millimeter, and the legs of the third pair are much dilated at their bases. The second kind, a pulsatoria, is larger, nearly two millimeters long, devoid of wings, and its eyes are minute. It is this second kind of death watch which makes such havoc in neglected collections of insects. Both divinatoria and pulsatoria produce a ticking sound, which is liable to be mistaken for the call of an anobium. It has been said that a tropis has no structures
in its body sufficiently hard to produce an audible sound, and that even when the ticking sound is heard and the atropus discovered, it is really an unseen anobium from which the sound proceeded. But the testimony in support of the ticking of atropus is too strong to be overpowered by mere opinions as to what it can or cannot do. One of my friends, a very keen observer, traced the ticking sound on five different occasions to an atropus, and in each case,
as soon as the insect was removed, the sound ceased. If we are to retain the name of Death Watch at all, we must recognize that it has no scientific value. There are several species of ticking insects, and they belong to widely different groups.
It is not difficult to abate the attacks of these small insects and to stop the destruction of furniture as well as the ticking sound. The infected object must first be discovered, and then an appropriate treatment can usually be devised. It is often most convenient to apply strong poisons in the form of vapor.
If the infected object can be placed in a tightly closed case, together with a saucer of carbon disulfide or benzene, and left for a few days, the beetles and their larvae will be killed. The eggs, however, are not necessarily destroyed, so that a watchfulness is necessary to prevent a recurrence of the attack.
In some cases, it is possible to wash the object with benzene or to plug the holes with furniture polish. Heat is very effectual, if it can be safely employed. A temperature of 80 degrees centigrade, maintained for some hours, destroys insects, larvae, and eggs alike.
End of chapter 42
