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INTRODUCTORY EDITORIAL NOTE v

INDEX 88

PLATE

FACING PAGE

BRITISH BUTTERFLIES

THE LIFE-HISTORY OF A BUTTERFLY

What is the difference between a butterfly and a moth, and how am I to distinguish between them? is a question very often put to the student of insect life--the entomologist.

The stages of development of butterflies and moths are practically the same: first the egg; next the caterpillar, or larva; then the pupa, or chrysalis; and, lastly, the imago, or perfect insect.

The eggs of the Lepidoptera are surpassingly beautiful. Are they like birds' eggs? Not at all! In the first place they are too minute for comparison with the larger product of the birds; both in colour and form they more nearly resemble small shells or pearls, as a great many of them are beautifully opalescent, especially when empty. A good hand-lens will reveal a great deal of their beauty, but the low power of an ordinary compound microscope will be necessary to enable you to see all the nice detail of pattern sculptured on their surfaces. Each species of butterfly, or moth, produces eggs of particular shape and ornamentation, so it is quite possible, in most cases, to say to which species an egg belongs. How long the egg may remain unhatched depends a good deal upon which butterfly's egg it is, the season of the year, and the temperature. Not many butterflies pass the winter in this country in the egg state, that season being usually passed either as a half-fed hibernating caterpillar, or as a chrysalis; and in a few cases it is only the female which passes the winter in some secure retreat, to emerge again in the spring, and then deposit her eggs on the fresh-growing verdure. But, generally speaking, eggs laid during the summer hatch out in from ten to sixteen days. And it is well to be on the lookout for the young larvae even earlier, if you intend to rear some species in confinement. If you have secured eggs to rear from, watch them from day to day to see if they darken, as they often assume a dark leaden hue immediately before hatching. This is a useful warning, and serves as a hint to have plenty of fresh food ready for the young family about to arrive.

The caterpillars are ravenous eaters; you will not notice this fact particularly at first, because they are then such tiny creatures, but in proportion to their size their eating capacity is enormous. They grow at an exceedingly rapid rate and to such an extent that they literally burst their skins! In a very short time--three or four days--the old skin bursts and out comes Mr. Caterpillar with a brand-new one. And this is the manner of their growth; several times this skin-shedding process is repeated. And then the creature prepares for the last and final change before turning into a butterfly.

You may at some time find a dozen or two larvae of some particular species of butterfly or moth, and at the time of collecting them they may seem healthy and all right, but weeks afterwards you may discover that only a very small number will change to chrysalids, the ichneumons having had the rest. If you can catch and induce a female butterfly to give you a batch of eggs in captivity, then you may be sure, providing your treatment of them has been right, that all your brood will arrive at the perfect state.

The next stage we have to consider we will pass over briefly. The change from the larva to the chrysalis is always a very fascinating performance to watch, not that one could sit and see the whole performance right through from start to finish, the time occupied is too long for that. Generally the process lasts a day or two, but by watching at frequent intervals, where several individuals are engaged at the same operation and each at its own stage of the work, it is not difficult to follow the whole process of the transformation. Try it with the larva of the Large Garden White butterfly, perhaps the commonest, and therefore the easiest to procure; you will gather plenty of "stung" or "ichneumoned" examples, but still a sufficient number should be clean to serve your purpose.

We will not enter into all the details of the "spinning-up" process and describe how an attachment is secured at the anal extremity, and how our little friend "loops the loop." Some species, such as the Tortoiseshell, get over this part of their difficulty by omitting the loop altogether, and therefore hang head downward, suspended only by the hooks and silk at the tail. Concealment during this stage is the creature's only hope and chance of survival; other defence they have none. Their colour may occasionally protect them by virtue of making them harmonize beautifully with their surroundings. The ichneumons seldom molest them during the chrysalis stage; but birds and small animals have sharp eyes when foraging for food, so it is usually far more difficult to discover these chrysalids than to find the feeding caterpillars.

The time passed as a chrysalis is very variable; ten days to a fortnight in summer is sufficient for many species; others pass over the whole winter, like the spring brood of our common white butterflies, so that these can be sought for during the winter months under the overhanging portion of palings, walls, outhouses, and in similar situations. The cold does not seem to injure them; it may, and generally does, retard their emergence, and possibly has some effect on the colours of the wings, but it cannot change their ultimate pattern. Experiments have been tried with various chrysalids, part of a brood being hatched out after being submitted to a very low temperature, and another part of the same brood after being treated with a high temperature. Speaking generally, the coloration of those subjected to the cold treatment was brightened and intensified, and Nature does the same thing in her own way. The early summer butterflies, which pass through the winter as chrysalids, are almost invariably larger and brighter than the midsummer or autumn brood of the same species.

But suppose our caterpillar to have successfully run the gauntlet--ichneumon, bird, beast, and beetle--and to have become a healthy pupa, and that the time has arrived when he must make the last and greatest transformation in his short and interesting career. Several days prior to his exit as a butterfly taking place, a noticeable change occurs in the apparent colour of the chrysalis.

As a matter of fact it is not the chrysalis shell which is changing colour, but the developing insect, the colours of which are beginning to show through it, at first rather faintly; but latterly the pattern of the wings can be distinctly seen, and the whole body surface gets darker. When this stage is reached, the advent of our butterfly is not long delayed. The hour chosen is usually early in the morning, so that by the time the sun is high and the fresh perfumed flowers are nodding in the breeze, our little butterfly has expanded and dried his wings, and is now quite prepared for the beautiful and consummating act in the wonderful drama of his existence.

While he is drying his wings and preparing for a life amongst sunshine and flowers, we might spend a few minutes with him ere he leaves us, and the more so, as now he looks his very best, arrayed in all his new-found finery. Such wings! no wonder he looks proud as he slowly opens and closes them, repeating this action over and over again as if to prove their smooth working before he launches forth upon the air.

And the wonderful pattern of these wings is all built up of tiny scales placed as regularly as the slates on a roof. Your pocket-lens will show you much of this, but to examine the individual scales, their various shapes and structure, you will require a compound microscope. These scales are the "dust" you will find on your finger and thumb if ever you pick up a butterfly in such an unscientific manner. You will notice, too, that the under sides of the wings bear quite a different design from the upper sides; this is nearly always the case, and in many foreign butterflies this difference between the two sides is so very remarkable as to be quite startling in its effect. Well I remember an old sergeant-major, who had spent many years in India, and had done a lot of "butterfly dodging" in his day, telling me of this wonderful effect. He said one would come upon an open piece of meadow-land blazing with flowers and butterflies, but, on being disturbed, the whole crowd of insects would rise in the air, and then, he would say, they looked like a different set altogether. When you capture a few specimens of any species, examine closely the under sides, and in any case, if you wish to preserve them, always set one of each sex with the under side uppermost.

Next to the wings the head claims our attention; it supports three very essential organs--the eyes, the horns, or antennae, and the tongue, or sucker.

The antennae are undoubtedly the organs of smell, which is perhaps the most highly developed sense in the Insect World. That the eyes are a marvel of beauty, and that the tongue is a finely finished little instrument for its work no one can question; but the sense of smell has a much longer range than even the eye, with all its facets. And you will generally find, in relation to the faculty which any animal or insect has to exert most so as to procure its food and propagate its kind, the organ of that faculty reaches the highest point of development and service.

The eyes of the condor and the gannet must be marvellous in range and penetrating power. I have watched scores of the latter birds sailing and hovering 150 feet and more above a troubled sea. Suddenly there would be a slight pause, and then a rocket-like dive right down into the waves below. To see a fish on the surface from such a height would be a great feat, but to see and catch one a dozen feet deep in a broken sea as a gannet can do, is wonderful indeed.

With butterfly and moth the sense of smell is of the greatest importance. Their vision is good, but short in range; so to find the flowers wherein lies their food the sight is good, but the power to detect them by scent must be far better. "Over the hedge is a garden fair," and if a butterfly cannot see through the hedge, he can at least smell through it. He could fly over it? Yes, but if his sense of smell says there is nothing there for him, you see he is saved the time and trouble; and his life is short.

"Assembling" and "treacling" for moths are two methods employed by insect-hunters to secure an abundance of specimens otherwise difficult to obtain, and in both cases it is this same wonderful sense of smell which is the insect's undoing.

A small portion of the eye makes a good slide for the microscope, but the individual lenses are hardly visible through an ordinary hand-glass. On the top of the head are one or two small simple eyes, which do not look as if they could be of much service, but one never knows, and the butterflies will not tell, although they have long tongues.

The tongue is a very pretty structure; when not in use it lies coiled up in spiral fashion like a watch-spring, and is then well protected by two little side-covers called the "palpi." Needless to say, the tongue cannot sting. No moth or butterfly has a stinging organ; the tongue is too delicate for any "cut and thrust" work. It is not difficult to mount a butterfly's tongue for the microscope, and its examination well repays the trouble. Particularly noticeable under the microscope are the little bell-shaped suckers placed in long rows near the tip. If you wish to make and examine a cross section, take the head of a freshly killed specimen and extend the tongue in a little melted paraffin wax; when this is thoroughly set, cut it across in very thin slices with a sharp razor; place one on a glass slide, then on to the microscope stage, and there you are! You will soon discover that the simple-looking tube is a very complicated affair, and quite a little study in itself.

We will not linger over what remains of the anatomy of our butterfly. The legs are six in number, but occasionally the first pair are useless for walking, and only the middle and last pairs are fully developed. Always remember the maximum number of legs for all insects is six. Caterpillars may have more or less; they occur as footless grubs with no legs at all, while some have as many as sixteen legs.

The last, or abdominal, section of a butterfly's body carries the sexual organs; it is usually more slender in the males than in the females.

THE CAPTURE AND PRESERVATION OF BUTTERFLIES

In the rearing of butterflies from eggs and in watching them all through their larval stages, we learn a great deal concerning their life and habits, and finally secure perfect specimens for the cabinet. But the glories of the chase and the charm of the country ramble weigh more in the balance with the naturalist, and the story of a captured specimen is often far more interesting than the record of a bred one.

Of butterfly nets used in the chase there are many and varied patterns in the market. I made my own and a better balanced one it would be hard to find. Having seen and handled a few in my time, my experience has been that they are mostly too heavy, have too many loose parts, and their weight is badly distributed. Indeed, I saw one lately which felt more like a hammer in one's hand. I think if you try to get one made after the pattern here described and figured on p. 15, you will not be disappointed with it.

The accompanying cut will show you how the eyes are turned and riveted, and how the nut is fixed in the tube which the tinsmith will make for you, and he will also solder the nut in the narrow end for a few coppers. Or you can get him to make the whole concern, as I have done for a friend of mine. I simply gave the tinsmith mine for a pattern, and in a few days he handed me over an exact duplicate, and only charged one shilling and sixpence for it.

The net itself is easily made. You will need 1-1/2 yards of the best and strongest muslin and a piece of stout twilled cotton, with which to make the hollow binding round the wire for strength. This binding must be at least 2 inches deep, so as to slip off and on the ring easily when you wish to repair the ring or wash the net. Get green muslin if you care for it; I tried green, too, but speedily gave it up, as I found the white net more effective for seeing and handling moths in after dark.

Do not shape the net down to too fine a point; rather make it more of a cup-shape and nearly the depth of your arm. And, lastly, while we are on the subject of the net, always carry a few strips of gum paper with you on an excursion; they are very handy and effective for repairing a damage, say, after contact with a bramble-bush.

Specially-made entomological pins can be purchased from all dealers in naturalists' requisites. Black enamelled pins are the vogue just now, and they last longer than the silvered or gilt ones, and resist "grease" better. Many insects, you should know, have a small, and some a large, amount of oil in their bodies, which gradually makes its presence seen, first in the abder possibly find the effect in the supposed cause by the most accurate scrutiny and examination. For the effect is totally different from the cause, and, consequently, can never be discovered in it.

Hence, we may discover the reason why no philosopher who is rational and modest has ever pretended to assign the ultimate cause of any natural operation, or to show distinctly the action of that power which produces any single effect in the universe.

The bread which I formerly ate nourished me; that is, a body of such sensible qualities was at that time endued with such secret powers; but does it follow that other bread must also nourish me at another time, and that like sensible qualities must always be attended with like secret powers? The consequence seems nowise necessary. At least, it must be acknowledged that there is here a consequence drawn by the mind, that there is a certain step taken; a process of thought, and an inference which wants to be explained.

These two propositions are far from being the same: "I have found that such an object has always been attended with such an effect," and: "I foresee that other objects, which are in appearance similar, will be attended with similar effects." I shall allow, if you please, that the one proposition may justly be inferred from the other; I know, in fact, that it always is inferred. But you must confess that the inference is not intuitive; neither is it demonstrative. Of what nature is it, then? To say it is experimental is begging the question. For all inferences from experience suppose, as their foundation, that the future will resemble the past, and that similar powers will be conjoined with similar sensible qualities.

If there be any suspicion that the course of nature may change, and that the past may be no rule for the future, all experience becomes useless, and can give rise to no inference or conclusion. It is impossible, therefore, that any arguments from experience can prove this resemblance of the past to the future, since all these arguments are founded on the supposition of that resemblance. Let the course of things be allowed hitherto ever so regular, that alone, without some new argument or inference, proves not that for the future it will continue so. In vain do you pretend to have learned the nature of bodies from your past experience. Their secret nature, and consequently all their effects and influence, may change without any change in their sensible qualities. This happens sometimes, and with regard to some objects. Why may it not happen always, and with regard to all objects? What logic, what process of argument, secures you against this supposition? My practice, you say, refutes my doubts. But you mistake the purport of my question. As an agent, I am quite satisfied on the point; but as a philosopher, who has some share of curiosity, I will not say scepticism, I want to learn the foundation of this inference.

Now, here arises a question on which the solution of the present difficulty will depend. Does it happen in all these relations that when one of the objects is presented to the senses or memory the mind is not only carried to the conception of the correlative, but reaches a steadier and stronger conception of it than otherwise it would have been able to attain? This seems to be the case with that belief which arises from the relation of cause and effect. And I shall add that it is conformable to the ordinary wisdom of nature to secure so necessary an act of the mind by some instinct or mechanical tendency, which may be infallible in its operations, may discover itself at the first appearance of life and thought, and may be independent of all the laboured deductions of the understanding.

When the fact attested is such a one as has seldom fallen under our observation, here is a contest of two possible experiences, of which the one destroys the other as far as its force goes, and the superior can only operate on the mind by the force which remains. The very same principle of experience which gives us a certain degree of assurance in the testimony of witnesses gives us also, in this case, another degree of assurance against the fact which they endeavour to establish, from which consideration there necessarily arises a counterpoise, and mutual destruction of belief and authority.

But in order to increase the probability against the testimony of witnesses, let us suppose that the fact which they affirm, instead of being only marvellous, is really miraculous; and suppose also that the testimony, considered apart and in itself, amounts to an entire proof, of which the strongest must prevail, but still with a diminution of its force in proportion to that of its antagonist.

A miracle is a violation of the laws of nature; and as a firm and unalterable experience has established these laws, the proof against a miracle, from the very nature of the fact, is as entire as any argument from experience can possibly be imagined. Why is it more than probable that all men must die; that lead cannot of itself remain suspended in the air; that fire consumes wood, and is extinguished by water; unless it be that these events are found agreeable to the laws of nature, and there is required a violation of these laws, or, in other words, a miracle, to prevent them?

The plain consequence is "that no testimony is sufficient to establish a miracle unless the testimony be of such a kind that its falsehood would be more miraculous than the fact which it endeavours to establish; and even in that case there is a mutual destruction of arguments, and the superior only gives us an assurance suitable to that degree of force which remains after deducting the inferior."

There surely never was a greater number of miracles ascribed to one person than those which were lately said to have been wrought in France upon the tomb of Abb? Paris, the famous Jansenist, with whose sanctity the people were so long deluded. The curing of the sick, giving hearing to the deaf and sight to the blind, were everywhere talked of as the usual effects of that holy sepulchre. But, what is more extraordinary, many of the miracles were immediately proved upon the spot before judges of unquestioned integrity, attested by witnesses of credit and distinction, in a learned age, and in the most eminent theatre that is now in the world.

Nor is this all; a relation of them was published and dispersed everywhere; nor were the Jesuits--though a learned body, supported by the civil magistrate and determined enemies to those opinions in whose favour the miracles were said to have been wrought--ever able distinctly to refute or detect them. Where shall we find such a number of circumstances agreeing to the corroboration of one fact? And what have we to oppose to such a cloud of witnesses but the absolute impossibility or miraculous nature of the events which they relate? And this surely, in the eyes of all reasonable people, will alone be regarded as a sufficient refutation.

Suppose that all the historians who treat of England should agree that on January 1, 1600, Queen Elizabeth died; that both before and after her death she was seen by her physicians and the whole court, as is usual with persons of her rank; that her successor was acknowledged and proclaimed by the Parliament; and that, after being interred a month, she again appeared, resumed the throne, and governed England for three years; I must confess that I should be surprised at the concurrence of so many odd circumstances, but should not have the least inclination to believe so miraculous an event. I should not doubt of her pretended death, and of those other public circumstances that followed it; I should only assert it to have been pretended, and that it neither was, nor possibly could be, real.

You would in vain object to me the difficulty and almost impossibility of deceiving the world in an affair of such consequence; the wisdom and solid judgment of that renowned queen; with the little or no advantage which she could reap from so poor an artifice. All this might astonish me; but I would still reply that the knavery and folly of men are such common phenomena that I should rather believe the most extraordinary events to arise from their concurrence than admit of so signal a violation of the laws of nature.

Upon reading this book we find it full of prodigies and miracles. It gives an account of a state of the world and of human nature entirely different from the present; of our fall from that state; of the age of man extended to near a thousand years; of the destruction of the world by a deluge; of the arbitrary choice of one people as the favourites of Heaven, and that people the countrymen of the author; of their deliverance from bondage by prodigies the most astonishing imaginable. I desire anyone to lay his hand upon his heart, and, after a serious consideration, declare whether he thinks that the falsehood of such a book, supported by such a testimony, would be more extraordinary and miraculous than the miracles it relates, which is, however, necessary to make it be received according to the measures of probability above established.

I was lately engaged in conversation with a friend who loves sceptical paradoxes. To my expression of the opinion that a wise magistrate can justly be jealous of certain tenets of philosophy such as those of Epicurus, which, denying a divine existence, and consequently a Providence and a future state, seem to loosen the ties of morality, he replied as follows.

"If Epicurus had been accused before the people he could easily have defended his cause and proved his principles of philosophy to be as salutary as those of his adversaries. And, if you please, I shall suppose myself Epicurus for a moment, and make you stand for the Athenian people."

EPICURUS: I come hither, O ye Athenians, to justify in your assembly what I maintained in my school, and I find myself impeached by furious antagonists instead of reasoning with calm and dispassionate inquirers.

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