WE are all of us but too familiar with the ravages of the common “Clothes Moth,” ever busy fretting both our garments and our tempers. We find our cherished furs and woollens – which we fondly imagined we had put away so carefully – utterly ruined by what we emphatically call the moth, as if but one species really existed, and we refuse it our interest and our sympathy. When we find some piece of material containing moth-larvæ, we are usually too intent upon destroying them to bestow much thought upon the habits of the creature; but I have discovered of late that even these moths are so curious as to be well worth a little careful study. I will relate how I came to know something about the life-history of some of the Tineæ, the name by which this species of insect is known.
Many years ago a friend gave me some beautiful grey feathers of birds which he had obtained during a voyage up the Nile. The majority of these feathers had been arranged in my feather-books, but a few remained in a drawer, and on examining them after a lapse of time I found they were shredded and perforated till only fragments were left. Quantities of little grey cases, or cocoons, showed that what had gained access to the feathers was moth. As I was then specially interested in the subject of domestic natural history, the living inmates of our houses, these cases were exactly what I wished to study. Accordingly I made a collection of them and covered them with a glass shade until I should find leisure to observe them more closely. Returning from some other occupation I found the small cases in active motion. A brown head and part of a white grub’s body appeared at one end, and each insect, like the Caddis Worm, was dragging its house after it and seemed able to crawl rapidly about. By gently pressing the tail-end of a cocoon I made the grub come out and leave its case behind, so that I could examine it more particularly. The case was evidently made of shreds of the feathers on which the grub had been feeding, and was lined with fine white silk.
There are understood to be about thirty-one species of Tinea in this country; of these many, when in the larva state, inhabit fungi or rotten wood. One beautiful species is found abundantly in granaries, its larva lives upon corn and resides in a case formed of wheat grains connected together by silken threads. Many of the species of Tineina, the great group to which the genus Tineæ belongs, are leaf-miners and form those white streaks we may often see upon bramble, honeysuckle, and strawberry leaves. The grubs of another kind may be found in Scotland, inhabiting ants’ nests, and even in a coal mine, near Glasgow, Tineæ have been found in abundance.
A very beautiful species of Tinea attacks the bark of the lime-tree until it becomes completely riddled by its destructive grubs. A fine avenue of about two hundred lime-trees forming one of the approaches to the town of Southampton was infested with this insect and the growth of the trees seriously injured by its ravages.
The furrier has cause to dread the ravages of Tinea Pellionella, which feeds on feathers and fur, and is no respecter of priceless sables and ermine. This insect makes its case with atoms of fur cut to the same length, and it works so insidiously that there is no outward sign of its evil doings until little tufts of fur begin to fall off, and then it is too late to save our valued garments. They are sure, sooner or later, to prove hopelessly destroyed.
Stuffed birds and animals can only be preserved from this annoying pest by being soaked in a strong solution of corrosive sublimate or some other poison. That this is effectual I have proved by the safe preservation of groups of stuffed birds which have hung against a wall exposed to the air without protection of any kind for the last twenty-five years; these are as fresh and bright in plumage now as when they were first obtained.
This fur-moth is perhaps the best known species in our houses; it is a small yellowish-grey insect with pale brown spots on the wings. This is, I believe, the species of which I have secured the larvæ. Fur and feathers are alike its staple diet, and it is easily distinguished from other kinds by a dark brown mark on the second segment of the grub, which mark I can discern by a magnifying glass.
The linings of chairs and sofas and the stuffing of carriage cushions, horse-hair pillows, &c., are constantly attacked by Tinea biselliella, while cloth, flannel, and any woollen material, suits the taste of the almost universal Tinea tapetzella, against whose ravages every housekeeper has to devise a variety of protective plans. The moth is so small it can creep through minute crevices – a knot-hole at the back of a drawer or a keyhole will afford it access to the winter garments which have been put away in supposed security.[7 - It would be a wise precaution to paste a piece of paper over the keyholes of drawers in which furs are kept during the summer, the moth could not then find access to their contents if the drawers are close-fitting.] Tapetzella differs in appearance from the fur moth as its wings are half black and half grey, and it is also of larger size. In laying her eggs the moth has the foresight to place them rather widely apart, so that each grub may find space enough in which to feed; it is this habit which renders the creature specially destructive, as it attacks many parts of a garment and does not confine its ravages to one spot. The larva of this species forms covered galleries in which it works, mining its way along the surface of the material, and eating off the pile wherever it goes and leaving threadbare tracks behind it.
Pellionella adopts a different method. The first work of the minute grub on issuing from the egg is to form a round case in which it may live, for it does not eat unless it has a house of its own. This curious habit may be seen in many other species amongst the Tineæ. I have already mentioned one which forms its house of wheat grains; another chooses particles of stone of which it constructs its dwelling, and then feeds on the lichens which grow upon old walls. Out of the fluffy seeds of the willow one Tinea forms a sort of muff in which it lives. Other species of the group form little tents upon the leaves of the elm, oak, and many kinds of fruit-trees, these cases being so minute as to be unobserved unless the insect is moving within. One of the most remarkable of all the species is one which inhabits the leaves of the nettle. The tent looks like a tiny hedgehog, as it is formed of minute portions of the leaf glued together and studded all over with the stinging hairs of the nettle.
Mr. James Rennie in his “Insect Architecture” gives such an excellent description of the weaving operations of the Pellionella grub that I cannot do better than quote his observations upon it: “It selected a single hair for the foundation of its intended structure; this it cut very near the skin in order, we suppose, to have as long as possible, and placed it in a line with its body. It then immediately cut another, and placing it parallel to the first, bound both together with a thread of its own silk. The same process was repeated with other hairs till the little creature had made a fabric of some thickness, and this it went on to extend till it was large enough to cover its body, which (as is usual with caterpillars) it employed as a model and measure for regulating its operations. The chamber was ultimately finished by a fine and closely woven tapestry of silk. When the caterpillar increases in length it takes care to add to the length of its house by working in fresh hairs at either end; and if it be shifted to furs or feathers of different colours it may be made to construct a parti-coloured tissue like a Scotch plaid. But the grub increases in thickness as well as in length, so that its first house becoming too narrow, it must either enlarge it or build a new one. It prefers enlarging the premises, and sets to work precisely as we should do, slitting the case on the two opposite sides and then adroitly inserting between them two pieces of the requisite size. When the structure is finished, the insect deems itself secure to feed upon the fur within its reach, provided it is dry and free from grease, which the grub will not touch.”
This account shows that the moth-grub can secrete a kind of silk with which it lines its cell, but it can use other materials out of which to weave a house for itself. When that house becomes too small it knows how to put in two side-pieces to make it fit the size of its body. When full grown, this same case forms its temporary coffin, for the little creature simply closes up the entrance and hangs itself up in some convenient place until in due time it comes out a perfect moth, ready to lay its eggs and pursue the instincts of its race. Surely we must admit that these lives which are carried on in our houses are very curious and worth investigation. When we think of the minute size of these grubs (scarcely a quarter of an inch in length) and the vigour of the instinct they display, the secret mode in which they work in airless drawers and boxes, the perseverance with which the moth finds entrance into these hiding-places, we must credit this small insect with many remarkable qualities. Its lineage is extremely ancient, for it is twice mentioned in the oldest book in the Bible, and it is not a little remarkable that Job seems to have been accurately acquainted with the habits of the Tinea larvæ, since he says, in speaking of an ungodly man, “He buildeth his house as a moth, and as a booth that the keeper maketh” (Job xxvii. 18).
Both of these images point to the temporary nature of the dwelling. A booth consists of a few branches put together at the top of a pole where a man can sit and scare away wild animals from the Eastern fields of fruit and grain – an erection easily removed in a few moments; it is appropriately likened to the moth grub’s tiny case which is cast aside after a few weeks or months, when the perfect insect has emerged. There are seven or eight allusions in the Scriptures to the ravages of the moth in destroying apparel, and remembering that Eastern people are in the habit of hoarding immense stores of richly embroidered clothing as an evidence of great wealth, there can be no doubt but that the many species of Tinea which are found in Palestine were a very real danger to be guarded against with the utmost solicitude.
THE DEATH-WATCH
“Alas! the poor gentleman will never get from hence,” said the Landlady to me, “for I heard the Death-Watch all night long.”
– Sterne.
A CURIOUS ticking sound is frequently heard in old houses full of ancient furniture, and especially during the still hours of the night. This noise, which I often hear in my own rooms, is attributed by the superstitious to some strange omen called the Death-Watch, and even in these enlightened days there are those who imagine it to presage the approaching decease of some one in the house.
But there is nothing really mysterious about it, and it will be well for us to learn all we can about this house-dweller, so that such an absurd idea may be entirely exploded.
The sound is really caused by a small beetle of nocturnal habits, the Anobium striatum. This insect is of dark brown colour and rather curious form, being so constructed that it can draw its head under the thorax out of sight, retract its six legs, and thus make itself into an oval pellet. It is seldom seen by day, unless a wall may have been newly papered; to such a wall the death-watches will often flock in considerable numbers, probably to feed upon the paste. If touched, the beetles feign to be dead, and they are so brittle as to be easily injured by handling. These insects do incredible damage by boring holes in valuable old furniture, musical instruments, panels, and skirting-boards, in fact hardly anything in the way of leather and woodwork is safe from the attack of this minute pest. The female beetle seeks a crevice in old wood, and with her ovipositor places a small white egg in it and firmly glues it in a suitable position. In twenty-one days the egg is hatched, and out of it comes a white grub much resembling that which we often find in filberts. This larva begins to bore into the wood, feeding upon it, and making those small round holes we often see to our regret in some valued piece of furniture.
The grub throws out the yellow dust of the wood – often the first indication of its being what we call “worm-eaten” – and when full grown it forms a cell in the wood in which it undergoes its change into the perfect beetle.
It is difficult to convince the ignorant that the ticking sound made by this insect is nothing more formidable than the call of the beetle to its mate! It strikes its hard-shelled head against the wood, and so gives rise to the clicking sound; other Anobiums hear it and reply in the same way, and thus the amorous duets and trios go on, often to the great annoyance of the sleepless and suffering. Do what we will, the little torments are beyond our reach, and nothing will avail to stop the noise, though on the other hand, if we wish to set it going I believe we can do so by tapping sharply upon any wainscot where the beetles are known to exist. It is strange to read how widely the fear of this insect noise has spread in other countries besides our own. Mr. John Timbs in his interesting book, “Things not Generally Known,” says: “The superstition about the Death-Watch extends from England to Cashmere, and across India diagonally to the remotest nook of Bengal, over three thousand miles distance from the entrance of the Indian Punjaub.”
The only effectual remedy for the ravages of this beetle appears to be pouring spirits of wine in which corrosive sublimate has been dissolved, into the minute holes; the spirit finds its way from one tunnel to another, and the beetles may be seen dropping out in numbers. If the piece of furniture is of large size it may require several applications to be effectual, but the process will render the wood distasteful to the insect, and probably stop its operations.
A beetle of an allied species, Anobium tessalatum, makes the same tapping sound in woodwork, and a minute insect, Atropos pulsatorius, which may frequently be found under the paper lining of picture-frames, is also credited with the power of making a clicking noise; but this can hardly be so loud as the sound of the ordinary Death-Watch beetle.
CHEESE-MITES AND FLIES
“O would the sons of men once think their eyes
And reason given them but to study flies.”
Pope’s Dunciad.
IT is not an altogether pleasant idea to dwell upon, that the very food we eat is sometimes tenanted by various forms of life. We can guard against meal-worms in the flour-barrel, and keep weevils from devouring our peas and beans; flies can be kept from the larder, and our dainties may be protected from the marauding cockroach; but by general consent we allow our cheese to be the home of a species of fungus, innumerable mites, and the grubs of a minute fly. Not only so, but most people prefer a Stilton or Cheddar cheese in a mitey condition, as it then possesses a heightened flavour. The first glimpse through a good microscope of a mass of cheese-mites is somewhat startling. We see a confused heap of struggling insects, and the idea of eating them at our next repast is by no means agreeable. Still they are worth examination as a type of a large class of animalcules which have for their object the destruction of many substances which might taint the air and do harm if they were allowed to remain in a state of decay.
The Cheese-mite has an almost transparent oval body tapering to a snout-like head. It can move with some agility upon its eight brownish-coloured legs. In sunlight this creature’s globular polished body shines as though it were made of crystal. This mite lays eggs abundantly, and also produces young alive, so this double mode of production may account for the rapid increase of the colonies in an ancient cheese.
The generic term Acarus includes a large number of species. There are those which, to the dismay of the entomologist, are found destroying his finest butterflies and moths, and reducing his cherished specimens to a little heap of dust. Some special kinds of mites prey upon figs, prunes, honeycomb, sugar, and sweetmeats of various kinds. A special mite is found in the cavities of the bones of skeletons; indeed, there seems scarcely any limit to this widely-spread family of minute depredators.
Other branches of the family are represented by the Red Spider, which is one of the plagues of our greenhouses, for, although so small as to be scarcely discernible by the naked eye, it sucks the juices of plants and often effectually prevents the healthy growth of valuable specimens.
The Plum-mite may frequently be seen in clusters upon fruit-trees, puncturing the bark and doing considerable injury to the smaller twigs.
A closely allied species is known as the Harvest-bug. This almost invisible atom burrows into the human skin and there deposits its eggs, causing excessive irritation and annoyance to the workers in corn-fields.
I will now turn from the mites to another cheese-inhabitant, Piophila casei. Few people are likely to have noticed the perfect insect, a small black fly with whitish wings margined with black; it is very inconspicuous, and we should hardly suspect its object in visiting our cheese. When cheeses are made and placed in a room to dry, before the outside rind has had time to harden, the Piophila will seek out some crevice in which to deposit its eggs. The creature is furnished with an ovipositor, which it can thrust out to a great length so as to penetrate to a considerable depth into the cracks of the cheese, and there it will lay as many as two hundred and fifty eggs. These hatch into white grubs without feet, but having two horny claw-shaped mandibles which enable them to bore into the cheese upon which they feed.
The breathing apparatus of the cheese-maggot is very remarkable, consisting of two tubes at the head and two at the tail, so the grub can breathe at either end of its body. Lest any particles of cheese should obstruct the front pair of tubes the little creature has the power of drawing over them a fold of the skin, and whilst they are thus closed it breathes through the air-tubes in the tail. A cheese inhabited by these grubs soon grows moist and rotten, because they have the power of emitting a liquid which softens and corrupts the cheese and renders it suitable for the food of the maggot.
The leaping power of these larvæ is truly surprising. Swammerdam, who seems to have carefully studied this creature, says: “I have seen one whose length did not exceed a fourth of an inch leap out of a box six inches deep, that is twenty-four times the length of its own body.” The grub cannot crawl, as it has no legs; it must therefore progress by leaps; this it achieves by erecting itself on its tail, which is furnished with several knobs or warts to enable it to keep its balance; then, bending itself into a ring, it lays hold of the skin of its tail, and, suddenly letting go with a jerk, it can, by a succession of springs, cover a surprising distance on a level surface. In considering the life-history of this despised creature I cannot but endorse the devout remark of the great naturalist I have just quoted. He says: “I can take upon me to affirm that the parts of this maggot are contrived with so much art and design that is impossible not to acknowledge them to be the work of infinite power and wisdom from which nothing is hid and to which nothing is impossible. It could not be the production of chance or rottenness, but the work of the same Omnipotent Hand which created the heavens and the earth.”
LEPISMÆ
LONG ago, I remember reading with enjoyment a little essay I met with somewhere, in which were described the various living creatures one would be likely to meet with in one’s garden, if one took a stroll at night with a lantern. Beetles would be seen crossing the path, worms moving stealthily in search of food, moths hovering over the flowers; if one were quiet and still for a little time even mice and shrews might be watched foraging about bent on their own special errands.
I have indulged in such a nocturnal garden ramble occasionally, but I think it needs younger eyes than mine now are, and perhaps exceptional weather to ensure a glimpse of nature on the prowl; at any rate, I have not been very fortunate in that way. My attention during the past year has been specially directed to house-dwelling creatures, and my rambles have been carried on indoors instead of in the garden. When I think of the life-histories of the Cork Moth, of the various Cloth Moths, of the Death-Watch, of the beetles I have found at work upon the specimens in my museum, of the Solitary bees and wasps in the crevices and angles of the outer brickwork of the house, and, finally, of the creature which I am now about to describe, I think it must be admitted that there is a field for entomological study inside as well as outside our dwellings.
Remembering that I once caught sight of some silvery fish-like insects upon the kitchen hearth, and afterwards watched a little pair of the same kind moving below a window-ledge in a bedroom, I determined to devote a little time to their investigation. I learned that they were called Lepisma saccherina, and that Linnæus formed the genus, and named it from the Greek word lepisma, a scale. The creatures are known as “The Bristle-tails proper”; the genus belongs to the order Thyasanura, which contains some extremely minute but very curious insects.
Sir John Lubbock’s researches have thrown much light upon the structure and habits of the Lepismidæ, and some of their near relations. I cannot help transcribing his description of the love-making of a couple of these atoms, known as Smerinthus luteus. Sir John says: “It is very amusing to see these little creatures coquetting together. The male, which is smaller than the female, runs round her, and they butt one another standing face to face, and moving backwards and forwards like two playful lambs. Then the female pretends to run away, and the male runs after her with a queer appearance of anger, gets in front and stands facing her again; then she turns coyly round, but he, quicker and more active, scuttles round too, and seems to whip her with his antennæ. Then for a bit they stand face to face, play with their antennæ, and seem to be all in all to one another.”
Sir John Lubbock considers the Lepismæ to be more nearly related to cockroaches than to any other form, but they do not in the least resemble those most unattractive creatures, being much smaller and of elegant shape, like slender little fishes made of silver. The body of a Lepisma consists of fourteen segments, the head being one, the thorax three, and the abdomen ten. The silvery scales which cover the body are so lightly attached, that a touch will bring them off. These scales have long been used as a test of power of microscopic lenses, the delicate markings on the scale being more or less visible according to the power of the glasses. The name Bristle-tail is given because of the seven caudal hairs which the Lepisma possesses, three of which are much longer than the rest. The Germans call these insects Borstenschwärze and Silberfischen (Bristle-tails and Silver-fishes).
Many insects seem to find wall paper an attractive diet, and the pair of Lepismæ I used to watch every night in the same place on the wall of my bedroom were evidently enjoying their evening meal, but as they lived in a dark corner and no very perceptible damage was done I did not interfere; when, however, the room was repapered I never saw these small visitants again.
I had a great wish to keep and study these singular creatures, and the only way to obtain them seemed to be by a nocturnal visit to my kitchen hearth, where I learned they were sometimes to be seen darting about in the warmth, seeking for such stray crumbs of sugar as they might find.
Happily this old house is not tenanted by cockroaches, else I should not have cared to intrude upon their domain in the witching hour of night; lepismas alone were to be seen gliding about, but how to catch them was a problem I found hard to solve. I tried various methods without success, and was about to retire quite discomfited by the exceeding swiftness of my quarry, when a bright idea occurred to me. With a sudden sweep of a small soft brush I wafted the insects on to a plate, and quickly transferred them into a glass globe. In this way I obtained nine perfect specimens, and was able to watch the beautiful little creatures, and admire their glistening bodies and agile movements.
I tried to cater for their rather bizarre diet by giving them a little sugar and cake, some wall paper and rotten wood. After a few days they lost all fear, and would come on my hand and daintily nibble a little sugar or cake offered them; they shunned the light and kept quiet through the day, coming out for active frolics in the evening.
A German naturalist says Lepismæ will gnaw holes in letter paper; in fact they seem to be omnivorous, for, like the cockroach, they will eat clothing, tapestry, and the silken trimmings of furniture. This insect seems to be found abundantly in India, for a lady has told me that her garments could not be laid aside for even a few days without swarms of these “silver fishes” gathering in the folds and creases. It shares with the Death-Watch a liking for paste, and this makes it attack the bindings of books, so that it is not an infrequent tenant of the shelves of damp, unused libraries, but from its small size I should imagine it cannot do any very serious amount of damage.
Whether my specimens will develop any interesting “habits” remains to be seen; they appear to be peaceable little folk, remaining quietly in the cracks and crevices of some rotten wood during the day, and towards evening they come forth to feed, and explore the bounds of their domain. Their legs are so short they cannot climb up the sides of the glass globe in which they live; it is therefore left open at the top, so that I am able to watch all that goes on, and may learn in time something of the life-history of Lepismæ.
POT-POURRI
“I plunge my hand among the leaves;
(An alien touch but dust perceives,
Nought else supposes;)
For me those fragrant ruins raise
Clear memory of the vanished days
When they were roses.”