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Yes: I was to find it. I even had it already in my possession. An urchin

of seven years, with an alert countenance, not washed every day, bare

feet, and dilapidated breeches supported by a piece of string, who

frequented the house as a dealer in turnips and tomatoes, arrived one

day with his basket of vegetables. Having received the few halfpence

expected by his mother as the price of the garden-stuff, and having

d them one by one into the hollow of his hand, he took from his

pocket an object which he had discovered the day before beneath a hedge

when gathering greenstuff for his rabbits.

"And this--will you have this?" he said, handing me the object. "Why,

certainly I will have it. Try to find me more, as many as you can, and

on Sunday you shall have lots of rides on the wooden horses. In the

meantime here is a penny for you. Don't forget it when you make up your

accounts; don't mix it with your turnip-money; put it by itself."

Beaming with satisfaction at such wealth, little touzle-head promised to

search industriously, already foreseeing a fortune.

When he had gone I examined the thing. It was worth examination. It was

a fine cocoon, thick and with blunt ends, very like a silkworm's cocoon,

firm to the touch and of a tawny colour. A brief reference to the

text-books almost convinced me that this was a cocoon of the _Bombyx

quercus_.[4] If so, what a find! I could continue my inquiry and perhaps

confirm what my study of the Great Peacock had made me suspect.

The Bombyx of the oak-tree is, in fact, a classic moth; indeed, there is

no entomological text-book but speaks of its exploits at mating-time. It

is said that a female emerged from the pupa in captivity, in the

interior of an apartment, and even in a closed box. It was far from the

country, amidst the tumult of a large city. Nevertheless, the event was

known to those concerned in the woods and meadows. Guided by some

mysterious compass, the males arrived, hastening from the distant

fields; they went to the box, fluttered against it, and flew to and fro

in the room.

These marvels I had learned by reading; but to see such a thing with

one's own eyes, and at the same time to devise experiments, is quite

another thing. What had my penny bargain in store for me? Would the

famous Bombyx issue from it?

Let us call it by its other name, the Banded Monk. This original name of

Monk was suggested by the costume of the male; a monk's robe of a modest

rusty red. But in the case of the female the brown fustian gives place

to a beautiful velvet, with a pale transversal band and little white

eyes on the fore pair of wings.

The Monk is not a common butterfly which can be caught by any one who

takes out a net at the proper season. I have never seen it around our

village or in the solitude of my grounds during a residence of twenty

years. It is true that I am not a fervent butterfly-catcher; the dead

insect of the collector's cabinet has little interest for me; I must

have it living, in the exercise of its functions. But although I have

not the collector's zeal I have an attentive eye to all that flies or

crawls in the fields. A butterfly so remarkable for its size and

colouring would never have escaped my notice had I encountered it.

The little searcher whom I had enticed by a promise of rides upon wooden

horses never made a second find. For three years I requisitioned friends

and neighbours, and especially their children, sharp-sighted snappers-up

of trifles; I myself hunted often under heaps of withered leaves; I

inspected stone-heaps and visited hollow tree-trunks. Useless pains; the

precious cocoon was not to be found. It is enough to say that the Banded

Monk is extremely rare in my neighbourhood. The importance of this fact

will presently appear.

As I suspected, my cocoon was truly that of the celebrated Oak Eggar. On

the 20th of August a female emerged from it: corpulent, big-bellied,

coloured like the male, but lighter in hue. I placed her under the usual

wire cover in the centre of my laboratory table, littered as it was with

books, bottles, trays, boxes, test-tubes, and other apparatus. I have

explained the situation in speaking of the Great Peacock. Two windows

light the room, both opening on the garden. One was closed, the other

open day and night. The butterfly was placed in the shade, between the

lines of the two windows, at a distance of 12 or 15 feet.

The rest of that day and the next went by without any occurrence worthy

of notice. Hanging by the feet to the front of the wire cover, on the

side nearest to the light, the prisoner was motionless, inert. There was

no oscillation of the wings, no tremor of the antennae, the female of the

Great Peacock behaved in a similar fashion.

The female Bombyx gradually matured, her tender tissues gradually

becoming firmer. By some process of which our scientists have not the

least idea she elaborated a mysterious lure which would bring her lovers

from the four corners of the sky. What was happening in this big-bellied

body; what transmutations were accomplished, thus to affect the whole


On the third day the bride was ready. The festival opened brilliantly. I

was in the garden, already despairing of success, for the days were

passing and nothing had occurred, when towards three in the afternoon,

the weather being very hot and the sun radiant, I perceived a crowd of

butterflies gyrating in the embrasure of the open window.

The lovers had at last come to visit their lady. Some were emerging from

the room, others were entering it; others, clinging to the wall of the

house, were resting as though exhausted by a long journey. I could see

others approaching in the distance, flying over the walls, over the

screens of cypress. They came from all directions, but at last with

decreasing frequency. I had missed the opening of the convocation, and

now the gathering was almost complete.

I went indoors and upstairs. This time, in full daylight and without

losing a detail, I witnessed once more the astonishing spectacle to

which the great nocturnal butterfly had first introduced me. The study

contained a cloud of males, which I estimated, at a glance, as being

about sixty in number, so far as the movement and confusion allowed me

to count them at all. After circling a few times over the cage many of

them went to the open window, but returned immediately to recommence

their evolutions. The most eager alighted on the cover, trampling on one

another, jostling one another, trying to get the best places. On the

other side of the barrier the captive, her great body hanging against

the wire, waited immovable. She betrayed not a sign of emotion in the

face of this turbulent swarm.

Going and entering, perched on the cover or fluttering round the room,

for more than three hours they continued their frenzied saraband. But

the sun was sinking, and the temperature was slowly falling. The ardour

of the butterflies also cooled. Many went out not to return. Others took

up their positions to wait for the gaieties of the following day; they

clung to the cross-bars of the closed window as the males of the Great

Peacock had done. The rejoicings were over for the day. They would

certainly be renewed on the morrow, since the courtship was without

result on account of the barrier of the wire-gauze cover.

But, alas I to my great disappointment, they were not resumed, and the

fault was mine. Late in the day a Praying Mantis was brought to me,

which merited attention on account of its exceptionally small size.

Preoccupied with the events of the afternoon, and absent-minded, I

hastily placed the predatory insect under the same cover as the moth.

It did not occur to me for a moment that this cohabitation could lead to

any harm. The Mantis was so slender, and the other so corpulent!

Alas! I little knew the fury of carnage animating the creature that

wielded those tiny grappling-irons! Next morning I met with a

disagreeable surprise: I found the little Mantis devouring the great

moth. The head and the fore part of the thorax had already disappeared.

Horrible creature! at what an evil hour you came to me! Goodbye to my

researches, the plans which I had caressed all night in my imagination!

For three years for lack of a subject, I was unable to resume them.

Bad luck, however, was not to make me forget the little I had learned.

On one single occasion about sixty males had arrived. Considering the

rarity of the Oak Eggar, and remembering the years of fruitless search

on the part of my helpers and myself, this number was no less than

stupefying. The undiscoverable had suddenly become multitudinous at the

call of the female.

Whence did they come? From all sides, and undoubtedly from considerable

distances. During my prolonged searches every bush and thicket and heap

of stones in my neighbourhood had become familiar to me, and I can

assert that the Oak Eggar was not to be found there. For such a swarm to

collect as I found in my laboratory the moths must have come from all

directions, from the whole district, and within a radius that I dare not

guess at.

Three years went by and by chance two more cocoons of the Monk or Oak

Eggar again fell into my hands. Both produced females, at an interval of

a few days towards the middle of August; so that I was able to vary and

repeat my experiments.

I rapidly repeated the experiments which had given me such positive

results in the instance of the Great Peacock moth. The pilgrims of the

day were no less skilful at finding their mates than the pilgrims of the

night. They laughed at all my tricks. Infallibly they found the

prisoners in their wire-gauze prisons, no matter in what part of the

house they were placed; they discovered them in the depths of a

wall-cupboard; they divined the secret of all manner of boxes, provided

these were not rigorously air-tight. They came no longer when the box

was hermetically sealed. So far this was only a repetition of the feats

of the Great Peacock.

A box perfectly closed, so that the air contained therein had no

communication with the external atmosphere, left the male in complete

ignorance of the recluse. Not a single one arrived, even when the box

was exposed and plain to see on the window-sill. Thus the idea of

strongly scented effluvia, which are cut off by screens of wood, metal,

card, glass, or what not, returns with double force.

I have shown that the great nocturnal moth was not thrown off the scent

by the powerful odour of naphthaline, which I thought would mask the

extra-subtle emanations of the female, which were imperceptible to human

olfactory organs. I repeated the experiment with the Oak Eggar. This

time I used all the resources of scent and stench that my knowledge of

drugs would permit.

A dozen saucers were arranged, some in the interior of the wire-gauze

cover, the prison of the female, and some around it, in an unbroken

circle. Some contained naphthaline; others the essential oil of

spike-lavender; others petroleum, and others a solution of alkaline

sulphur giving off a stench of rotten eggs. Short of asphyxiating the

prisoner I could do no more. These arrangements were made in the

morning, so that the room should be saturated when the congregation of

lovers should arrive.

In the afternoon the laboratory was filled with the most abominable

stench, in which the penetrating aroma of spike-lavender and the stink

of sulphuretted hydrogen were predominant. I must add that tobacco was

habitually smoked in this room, and in abundance. The concerted odours

of a gas-works, a smoking-room, a perfumery, a petroleum well, and a

chemical factory--would they succeed in confusing the male moths?

By no means. About three o'clock the moths arrived in as great numbers

as usual. They went straight to the cage, which I had covered with a

thick cloth in order to add to their difficulties. Seeing nothing when

once they had entered, and immersed in an extraordinary atmosphere in

which any subtle fragrance should have been annihilated, they

nevertheless made straight for the prisoner, and attempted to reach her

by burrowing under the linen cloth. My artifice had no result.

After this set-back, so obvious in its consequences, which only repeated

the lesson of the experiments made with naphthaline when my subject was

the Great Peacock, I ought logically to have abandoned the theory that

the moths are guided to their wedding festivities by means of strongly

scented effluvia. That I did not do so was due to a fortuitous

observation. Chance often has a surprise in store which sets us on the

right road when we have been seeking it in vain.

One afternoon, while trying to determine whether sight plays any part in

the search for the female once the males had entered the room, I placed

the female in a bell-glass and gave her a slender twig of oak with

withered leaves as a support. The glass was set upon a table facing the

open window. Upon entering the room the moths could not fail to see the

prisoner, as she stood directly in the way. The tray, containing a layer

of sand, on which the female had passed the preceding day and night,

covered with a wire-gauze dish-cover, was in my way. Without

premeditation I placed it at the other end of the room on the floor, in

a corner where there was but little light. It was a dozen yards away

from the window.

The result of these preparations entirely upset my preconceived ideas.

None of the arrivals stopped at the bell-glass, where the female was

plainly to be seen, the light falling full upon her prison. Not a

glance, not an inquiry. They all flew to the further end of the room,

into the dark corner where I had placed the tray and the empty


They alighted on the wire dome, explored it persistently, beating their

wings and jostling one another. All the afternoon, until sunset, the

moths danced about the empty cage the same saraband that the actual

presence of the female had previously evoked. Finally they departed: not

all, for there were some that would not go, held by some magical

attractive force.

Truly a strange result! The moths collected where there was apparently

nothing to attract them, and remained there, unpersuaded by the sense of

sight; they passed the bell-glass actually containing the female without

halting for a moment, although she must have been seen by many of the

moths both going and coming. Maddened by a lure, they paid no attention

to the reality.

What was the lure that so deceived them? All the preceding night and all

the morning the female had remained under the wire-gauze cover;

sometimes clinging to the wire-work, sometimes resting on the sand in

the tray. Whatever she touched--above all, apparently, with her

distended abdomen--was impregnated, as a result of long contact, with a

certain emanation. This was her lure, her love-philtre; this it was that

revolutionised the Oak Eggar world. The sand retained it for some time

and diffused the effluvium in turn.

They passed by the glass prison in which the female was then confined

and hastened to the meshes of wire and the sand on which the magic

philtre had been poured; they crowded round the deserted chamber where

nothing of the magician remained but the odorous testimony of her


The irresistible philtre requires time for its elaboration. I conceive

of it as an exhalation which is given off during courtship and gradually

saturates whatever is in contact with the motionless body of the female.

If the bell-glass was placed directly on the table, or, still better, on

a square of glass, the communication between the inside and the outside

was insufficient, and the males, perceiving no odour, did not arrive so

long as that condition of things obtained. It was plain that this

failure of transmission was not due to the action of the glass as a

screen simply, for if I established a free communication between the

interior of the bell-glass and the open air by supporting it on three

small blocks, the moths did not collect round it at once, although there

were plenty in the room; but in the course of half an hour or so the

feminine alembic began to operate, and the visitors crowded round the

bell-glass as usual.

In possession of these data and this unexpected enlightenment I varied

the experiments, but all pointed to the same conclusion. In the morning

I established the female under the usual wire-gauze cover. For support I

gave her a little twig of oak as before. There, motionless as if dead,

she crouched for hours, half buried in the dry leaves, which would thus

become impregnated with her emanations.

When the hour of the daily visits drew near I removed the twig, which

was by then thoroughly saturated with the emanations, and laid it on a

chair not far from the open window. On the other hand I left the female

under the cover, plainly exposed on the table in the middle of the room.

The moths arrived as usual: first one, then two, then three, and

presently five and six. They entered, flew out again, re-entered,

mounted, descended, came and went, always in the neighbourhood of the

window, not far from which was the chair on which the twig lay. None

made for the large table, on which, a few steps further from the window,

the female awaited them in the wire-gauze cover. They hesitated, that

was plain; they were still seeking.

Finally they found. And what did they find? Simply the twig, which that

morning had served the ample matron as bed. Their wings rapidly

fluttering, they alighted on the foliage; they explored it over and

under, probed it, raised it, and displaced it so that the twig finally

fell to the floor. None the less they continued to probe between the

leaves. Under the buffets and the draught of their wings and the

clutches of their eager feet the little bundle of leaves ran along the

floor like a scrap of paper patted by the paws of a cat.

While the twig was sliding away with its band of investigators two new

arrivals appeared. The chair lay in their path. They stopped at it and

searched eagerly at the very spot on which the twig had been lying. But

with these, as with the others, the real object of their desires was

there, close by, under a wire cover which was not even veiled. None took

any note of it. On the floor, a handful of butterflies were still

hustling the bunch of leaves on which the female had reposed that

morning; others, on the chair, were still examining the spot where the

twig had lain. The sun sank, and the hour of departure struck. Moreover,

the emanations were growing feebler, were evaporating. Without more ado

the visitors left. We bade them goodbye till the morrow.

The following tests showed me that the leaf-covered twig which

accidentally enlightened me might be replaced by any other substance.

Some time before the visitors were expected I placed the female on a bed

of cloth or flannel, card or paper. I even subjected her to the rigours

of a camp-bed of wood, glass, marble, and metal. All these objects,

after a contact of sufficient duration, had the same attraction for the

males as the female moth herself. They retained this property for a

longer or shorter time, according to their nature. Cardboard, flannel,

dust, sand, and porous objects retained it longest. Metals, marble, and

glass, on the contrary, quickly lost their efficacy. Finally, anything

on which the female had rested communicated its virtues by contact;

witness the butterflies crowding on the straw-bottomed chair after the

twig fell to the ground.

Using one of the most favourable materials--flannel, for example--I

witnessed a curious sight. I placed a morsel of flannel on which the

mother moth had been lying all the morning at the bottom of a long

test-tube or narrow-necked bottle, just permitting of the passage of a

male moth. The visitors entered the vessels, struggled, and did not know

how to extricate themselves. I had devised a trap by means of which I

could exterminate the tribe. Delivering the prisoners, and removing the

flannel, which I placed in a perfectly closed box, I found that they

re-entered the trap; attracted by the effluvia that the flannel had

communicated to the glass.

I was now convinced. To call the moths of the countryside to the

wedding-feast, to warn them at a distance and to guide them the nubile

female emits an odour of extreme subtlety, imperceptible to our own

olfactory sense-organs. Even with their noses touching the moth, none of

my household has been able to perceive the faintest odour; not even the

youngest, whose sensibility is as yet unvitiated.

This scent readily impregnates any object on which the female rests for

any length of time, when this object becomes a centre of attraction as

active as the moth herself until the effluvium is evaporated.

Nothing visible betrays the lure. On a sheet of paper, a recent

resting-place, around which the visitors had crowded, there was no

visible trace, no moisture; the surface was as clean as before the


The product is elaborated slowly, and must accumulate a little before it

reveals its full power. Taken from her couch and placed elsewhere the

female loses her attractiveness for the moment and is an object of

indifference; it is to the resting-place, saturated by long contact,

that the arrivals fly. But the female soon regains her power.

The emission of the warning effluvium is more or less delayed according

to the species. The recently metamorphosed female must mature a little

and her organs must settle to their work. Born in the morning, the

female of the Great Peacock moth sometimes has visitors the night of the

same day; but more often on the second day, after a preparation of forty

hours or so. The Oak Eggar does not publish her banns of marriage before

the third or fourth day.

Let us return for a moment to the problematical function of the antennae.

The male Oak Eggar has a sumptuous pair, as has the Great Peacock or

Emperor Moth. Are we to regard these silky "feelers" as a kind of

directing compass?--I resumed, but without attaching much importance to

the matter, my previous experiment of amputation. None of those operated

on returned. Do not let us draw conclusions from that fact alone. We saw

in the case of the Great Peacock that more serious reasons than the

truncation of the antennae made return as a rule impossible.

Moreover, a second Bombyx or Eggar, the Clover Moth, very like the Oak

Eggar, and like it superbly plumed, poses us a very difficult problem.

It is fairly abundant around my home; even in the orchard I find its

cocoon, which is easily confounded with that of the Oak Eggar. I was at

first deceived by the resemblance. From six cocoons, which I expected to

yield Oak Eggars, I obtained, about the end of August, six females of

the other species. Well: about these six females, born in my house,

never a male appeared, although they were undoubtedly present in the


If the ample and feathery antennae are truly sense-organs, which receive

information of distant objects, why were not my richly plumed neighbours

aware of what was passing in my study? Why did their feathery "feelers"

leave them in ignorance of events which would have brought flocks of the

other Eggar? Once more, the organ does not determine the aptitude. One

individual or species is gifted, but another is not, despite an organic