Next to our garments our houses and buildings, which shelter us and our property from the inclemency and injuries of the atmosphere, are of consequence to us: yet these, solid and substantial as they appear, are not secure from the attack of insects; and even our furniture often suffers from them. A great part of our comfort within doors depends upon our apartments being kept clean and neat. Spiders by their webs, which they suspend in every angle, and flies by their excrements, which they scatter indiscriminately upon every thing, interfere with this comfort, and add much to the business of our servants. Even ants will sometimes plant their colonies in our kitchens, (I have known the horse-ant, Formica rufa, do this,) and are not easily expelled. Those of Sierra Leone, as I was once informed by the learned Professor Afzelius, make their way by millions through the houses. They resolutely pursue a straight course; and neither buildings nor rivers, even though myriads perish in the attempt, can divert them from it. Numerous are the tribes of insects that seek their food in our timber, whether laid up in store for our future use, employed in our houses, buildings, gates or fences, or made up into furniture. The several species of Mr. Marsham's genus Ips (which includes the coleopterous genera Apate, Bostrichus, Hylessinus, Hylurgus, Tomicus, Platypus, Scolytus, and Phloiotribus of modern systematists) all prey upon timber, feeding between the bark and the wood, and many of them excavating curious pinnated labyrinths. Almost every kind of tree has a species of this genus appropriated to it, and some have more than one[428]. The Stag-beetle tribe, or Lucanidæ, and several of the weevils[429], have a similar appetite, but penetrate deeper into the wood. The most extensive family, however, of timber-borers are the capricorn beetles, including the Fabrician genera of Prionus, Cerambyx, Lamia[430], Stenocorus, Calopus, Rhagium, Gnoma, Saperda, Callidium, and Clytus. The larva of these, as soon as hatched, leaves its first station between the bark and wood, and begins to make its way into the solid timber, (some of them plunging even into the iron heart of the oak, and one even perforating lead[431],) where it eats for itself tortuous paths, at its first starting perhaps not bigger than a pin's head, but gradually increasing in dimensions as the animal increases in magnitude, till it attains in some instances to a diameter of one or two inches. Only conceive what havoc the grub of the vast Prionus giganteus must make in a beam! Percival is probably speaking of this beetle, when, in his account of Ceylon, he tells us, "There is an insect found here which resembles an immense over-grown beetle. It is called by us a carpenter, from its boring large holes in timber, of a regular form, and to the depth of several feet, in which, when finished, it takes up its habitation[432]." Seeing the perfect insect come out of these holes, an unentomological observer would naturally conclude that the beetle he saw had formed it, and lived in it; but, doubtless, the whole was the work of the grub[433].—Of all the coleopterous genera there is none the species of which are generally so rich, resplendent and beautiful as those of Buprestis: these likewise, in their first state, there is abundant reason to believe, derive their nutriment from the produce of the forest, in which they sometimes remain for many years before they assume their perfect state, and appear in their full splendour, as if nature required more time than usual to decorate these lovely insects. We learn from Mr. Marsham, that the grub of B. splendida was ascertained to have existed in the wood of a deal table more than twenty years[434].—In this enumeration of timber-eating beetles, I must not forget the Fabrician genera, Anobium and Ptilinus, because of one of them (Anobium pertinax) Linné complains "terebravit et destruxit sedilia mea[435];" and I can renew the same complaint against A. striatum, which not only has destroyed my chairs, but also picture-frames, and has perforated in every direction the deal floor of my chamber, from which it annually emerges through little round apertures in great numbers.—The utility of entomological knowledge in economics was strikingly exemplified, when the great naturalist just mentioned, at the desire of the king of Sweden, traced out the cause of the destruction of the oak-timber in the royal dock-yards; and, having detected the lurking culprit under the form of a beetle, (Lymexylon navale) by directing the timber to be immersed during the time of the metamorphosis of that insect and its season of oviposition, furnished a remedy which effectually secured it from its future attacks[436].—No coleopterous insects are more singular than those that belong to the genus Pausus, L.; and one of them at least, remarkable for emitting a phosphoric light from the globes of its antennæ, is also a timber-feeder[437].—Amongst the Hymenoptera there are many insects that injure us in this department. The species of the genus Sirex, probably all of them in their larva state, have no appetite but for ligneous food. Linné has observed this with respect to S. Spectrum and Camelus; and Mr. Marsham, on the authority of Sir Joseph Banks, relates that several specimens of S. Gigas were seen to come out of the floor of a nursery in a gentleman's house, to the no small alarm and discomfiture of both nurse and children[438].—The genus Trypoxylon, many species of Crabro, Eumenes Parietum, Latreille's genera Xylocopa, Chelostoma, Heriades, Megachile and Anthophora, (all separated from Apis, L.,) perforate posts and rails and other timber, to form cells for their young[439].
The Linnean order Aptera furnishes another timber-eating insect, a kind of wood-louse, though scarcely an eighth of the size of the common one, (Limnoria terebrans of Dr. Leach,) which in point of rapidity of execution seems to surpass all its European brethren, and in many cases may be productive of more serious injury than any of them, since it attacks the wood-work of piers and jetties constructed in salt-water, and so effectually, as to threaten the rapid destruction of those in which it has established itself. In December 1815 I was favoured by Charles Lutwidge, esq. of Hull, with specimens of wood from the piers at Bridlington Quay which wofully confirm the fears entertained of their total ruin by the hosts of these pygmy assailants that have made good a lodgement in them, and which, though not so big as a grain of rice, ply their masticatory organs with such assiduity as to have reduced great part of the wood-work into a state resembling honey-comb. One specimen was a portion of a three-inch fir plank nailed to the North Pier about three years since, which is now crumbled away to less than an inch in thickness—in fact, deducting the space occupied by the cells which cover both surfaces as closely as possible, barely half an inch of solid wood is left; and though its progress is slower in oak, that wood is equally liable to be attacked by it.—If this insect were easily introduced to new stations, it might soon prove as destructive to our jetties as the Teredo navalis to those of Holland, and induce the necessity of substituting stone for wood universally, whatever the expense: but happily it seems endowed with very limited powers of migration; for, though it has spread along both the South and East Piers of Bridlington harbour, it has not yet, as Mr. Lutwidge informs me, reached the dolphin nor an insulated jetty within the harbour.—No other remedy against its attacks is known than that of keeping the wood free from salt-water for three or four days, in which case it dies; but this method it is obvious can be rarely applicable[440].
How dear are their books, their cabinets of the various productions of nature, and their collections of prints and other works of art and science, to the learned, the scientific, and the virtuosi! Even these precious treasures have their insect enemies. The larva of Aglossa pinguinalis, whose ravages in another quarter I have noticed before[441], will establish itself upon the binding of a book, and spinning a robe, which it covers with its own excrement[442], will do it no little injury. A mite (Cheyletus eruditus) eats the paste that fastens the paper over the edges of the binding, and so loosens it[443]. I have also often observed the caterpillar of another little moth, of which I have not ascertained the species, that takes its station in damp old books, between the leaves, 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 destroyers from the hands of book-collectors. The little wood-boring beetles before mentioned (Anobium pertinax and striatum) also attack books, and will even bore through several volumes. M. Peignot mentions an instance where, in a public library but little frequented, twenty-seven folio volumes were perforated in a straight line by the same insect, (probably one of these species,) in such a manner that on passing a cord through the perfectly round hole made by it, these twenty-seven volumes could be raised at once[444]. The animals last mentioned also destroy prints and drawings, whether framed, or preserved in a porte-feuille. Our collections of quadrupeds, birds, insects and plants have likewise several terrible insect enemies, which without pity or remorse often destroy or mutilate our most highly prized specimens. Ptinus Fur and Anthrenus Musæorum, two minute beetles, are amongst the worst, especially the latter, whose singular gliding larva, when once it gets amongst them, makes astonishing havoc, the birds soon shedding their feathers, and the insects falling to pieces. Mr. W. S. MacLeay informs me that at the Havana it is exceedingly difficult to preserve insects, &c., as the ants devour every thing.—One of the worst plagues of the entomologist is a mite (Acarus Destructor, Schrank): this, if his specimens be at all damp, eats up all the muscular parts, (Cantharis vesicatoria being almost the only insect that is not to its taste,) and thus entirely destroys them.—If spiders by any means get amongst them, they will do no little mischief.—Some I have observed to be devoured by a minute moth, perhaps Tinea Insectella; and in the posterior thighs of a species of Locusta from China, I once found, one in each thigh, a small beetle congenerous with Antherophagus pallens, that had devoured the interior. It is, I believe, either Acarus Destructor or Cheyletus eruditus that eats the gum employed to fasten down dried plants.
There are other insects which do not confine themselves to one or two articles, but make a general and indiscriminate attack upon our dead stock. Ulloa mentions one peculiar to Carthagena, called there the comegen, which he describes as a kind of moth or maggot so minute as to be scarcely visible to the naked eye[445]. This destroys, says he, the furniture of houses, particularly all kinds of hangings, whether of cloth, linen, or silk, gold or silver stuffs or lace; in short, every thing except solid metal. It will in a single night ruin all the goods of a warehouse in which it has got footing, reducing bales of merchandize to dust without altering their appearance, so that the mischief is not perceived till they come to be handled[446]. If we make some deduction from this account for exaggeration, still the amount of damage will be very considerable.
There are three kinds of insects better known, to whose ravages, as most prominent and celebrated, I shall last call your attention. The insects I mean are the cock-roach (Blatta orientalis), the house-cricket (Gryllus domesticus), and the various species of white ants (Termes). The last of these, most fortunately for us, are not yet naturalized.
The cock-roaches hate the light, at least the kind that is most abundant in Britain, (for B. germanica, which abounds in some houses, is bolder, making its appearance in the day, and running up the walls and over the tables, to the great annoyance of the inhabitants,) and never come forth from their hiding-places till the lights are removed or extinguished. In the London houses, especially on the ground-floor, they are most abundant, and consume every thing they can find, flour, bread, meat, clothes, and even shoes[447]. As soon as light, natural or artificial, re-appears, they all scamper off as fast as they can, and vanish in an instant. These pests are not indigenous here, and perhaps no where in Europe, but are one of the evils which commerce has imported: and we may think ourselves well off that others of the larger species of the genus have not been introduced in the same way—as, for instance, Blatta gigantea, a native of Asia, Africa, and America, many times the size of the common one,—which, not content with devouring meat, clothes and books, even attacks persons in their sleep, and the extremities of the dead and dying[448].
The house-cricket may perhaps be deemed a still more annoying insect than the common cock-roach, adding an incessant noise to its ravages; since, although, for a short time, it may not be unpleasant to hear
"the cricket chirrup in the hearth,"
so constant a din every evening must very much interrupt comfort and conversation. These garrulous animals, which live in a kind of artificial torrid zone, are very thirsty souls, and are frequently found drowned in pans of water, milk, broth, and the like. Whatever is moist, even stockings or linen hung out to dry, is to them a bonne bouche; they will eat the scummings of pots, yeast, crumbs of bread, and even salt, or any thing within their reach. Sometimes they are so abundant in houses as to become absolute pests, flying into the candles and into people's faces.
At Cuddapa, in the ceded districts to the northward of Mysore, Captain Green was much annoyed by a jumping insect, which from his description I should take for the larva of a species of cricket. They were of a dun colour, and from half to three-fourths of an inch in length. They abounded at night, and were very injurious to papers and books, which they both discoloured and devoured; leather also was eaten by them. Such was their boldness and avidity, that they attacked the exposed parts of the body when you were asleep, nibbling the ends of the fingers, particularly the skin under the nails, which was only discoverable by a slight soreness that succeeded. So great was their agility that they could seldom be caught or crushed. They were a mute insect, but probably the imago would make noise enough.