THE CICADA: HIS MUSIC

By his own confession, Réaumur never heard the Cicada sing; he never saw the insect alive. It reached him from the country round Avignon preserved in spirits and a goodly supply of sugar. These conditions were enough to enable the anatomist to give an exact description of the organ of sound; nor did the master fail to do so: his penetrating eye clearly discerned the construction of the strange musical-box, so much so that his treatise upon it has become the fountain-head for any one who wants to say a few words about the Cicada’s song.

With him the harvest was gathered; it but remains to glean a few ears which the disciple hopes to make into a sheaf. I have more than enough of what Réaumur lacked: I hear rather more of these deafening symphonists than I could wish; and so I shall perhaps obtain a little fresh light on a subject [59]that seems exhausted. Let us therefore go back to the question of the Cicada’s song, repeating only so much of the data acquired as may be necessary to make my explanation clear.

In my neighbourhood I can capture five species of Cicadæ, namely, Cicada plebeia, Lin.; C. orni, Lin.; C. hematodes, Lin.; C. atra, Oliv.; and C. pygmæa, Oliv. The first two are extremely common; the three others are rarities, almost unknown to the country-folk.

The Common Cicada is the biggest of the five, the most popular and the one whose musical apparatus is usually described. Under the male’s chest, immediately behind the hind-legs, are two large semicircular plates, overlapping each other slightly, the right plate being on the top of the left. These are the shutters, the lids, the dampers, in short the opercula of the organ of sound. Lift them up. You then see opening, on either side, a roomy cavity, known in Provence by the name of the chapel (li capello). The two together form the church (la glèiso). They are bounded in front by a soft, thin, creamy-yellow membrane; at the back by a dry pellicle, iridescent as a soap-bubble [60]and called the mirror (mirau) in the Provençal tongue.

The church, the mirrors and the lids are commonly regarded as the sound-producing organs. Of a singer short of breath it is said that he has cracked his mirrors (a li mirau creba). Picturesque language says the same thing of an uninspired poet. Acoustics give the lie to the popular belief. You can break the mirrors, remove the lids with a cut of the scissors, tear the yellow front membrane and these mutilations will not do away with the Cicada’s song: they simply modify it, weaken it slightly. The chapels are resonators. They do not produce sound, they increase it by the vibrations of their front and back membranes; they change it as their shutters are opened more or less wide.

The real organ of sound is seated elsewhere and is not easy to find, for a novice. On the other side of each chapel, at the ridge joining the belly to the back, is a slit bounded by horny walls and masked by the lowered lid. Let us call it the window. This opening leads to a cavity or sound-chamber deeper than the adjacent chapel, but much less wide. Immediately behind the attachment of the [61]rear wings is a slight, almost oval protuberance, which is distinguished by its dull-black colour from the silvery down of the surrounding skin. This protuberance is the outer wall of the sound-chamber.

Let us make a large cut in it. We now lay bare the sound-producing apparatus, the cymbal. This is a little dry, white membrane, oval-shaped, convex on the outside, crossed from end to end of its longer diameter by a bundle of three or four brown nervures, which give it elasticity, and fixed all round in a stiff frame. Imagine this bulging scale to be pulled out of shape from within, flattening slightly and then quickly recovering its original convexity owing to the spring of its nervures. The drawing in and blowing out will produce a clicking sound.

Twenty years ago, all Paris went mad over a silly toy called the Cricket, or Cri-cri, if I remember rightly. It consisted of a short blade of steel, fastened at one end to a metallic base. Alternately pressed out of shape with the thumb and then released, the said blade, though possessing no other merit, gave out a very irritating click; and nothing more was needed to make it popular. The [62]Cricket’s vogue is over. Oblivion has done justice to it so drastically that I doubt if I shall be understood when I recall the once famous apparatus.

The membranous cymbal and steel Cricket are similar instruments. Both are made to rattle by pushing an elastic blade out of shape and restoring it to its original condition. The Cricket was bent out of shape with the thumb. How is the convexity of the cymbals modified? Let us go back to the church and break the yellow curtain that marks the boundary of each chapel in front. Two thick muscular columns come in sight, of a pale orange colour, joined together in the form of a V, with its point standing on the insect’s median line, on the lower surface. Each of these fleshy columns ends abruptly at the top, as though lopped off; and from the truncated stump rises a short, slender cord which is fastened to the side of the corresponding cymbal.

There you have the whole mechanism, which is no less simple than that of the metal Cricket. The two muscular columns contract and relax, shorten and lengthen. By means of the terminal thread each tugs at its cymbal, pulling it down and forthwith letting [63]it spring back of itself. Thus are the two sound-plates made to vibrate.

Would you convince yourself of the efficacy of this mechanism? Would you make a dead but still fresh Cicada sing? Nothing could be simpler. Seize one of the muscular columns with the pincers and jerk it gently. The dead Cri-cri comes to life again; each jerk produces the clash of the cymbal. The sound is very feeble, I admit, deprived of the fulness which the living virtuoso obtains with the aid of his sound-chambers; nevertheless the fundamental element of the song is produced by this anatomical trick.

Would you on the other hand silence a live Cicada, that obstinate melomaniac who, when you hold him prisoner in your fingers, bewails his sad lot as garrulously as, just now, he sang his joys in the tree? It is no use to break open his chapels, to crack his mirrors: the shameful mutilation would not check him. But insert a pin through the side slit which we have called the window and touch the cymbal at the bottom of the sound-chamber. A tiny prick; and the perforated cymbal is silent. A similar operation on the other side renders the insect mute, though it remains as vigorous as before, showing [64]no perceptible wound. Any one unacquainted with the method of procedure stands amazed at the result of my pin-prick, when the utter destruction of the mirrors and the other accessories of the church does not produce silence. A tiny and in no way serious stab has an effect which is not caused even by evisceration.

The lids, those firmly fitted plates, are stationary. It is the abdomen itself which, by rising and falling, causes the church to open and shut. When the abdomen is lowered, the lids cover the chapels exactly, together with the windows of the sound-chambers. The sound is then weakened, muffled, stifled. When the abdomen rises, the chapels open, the windows are unobstructed and the sound acquires its full strength. The rapid oscillations of the belly, therefore, synchronizing with the contractions of the motor-muscles of the cymbals, determine the varying volume of the sound, which seems to come from hurried strokes of a bow.

When the weather is calm and warm, about the middle of the day, the Cicada’s song is divided into strophes of a few seconds’ duration, separated by short pauses. [65]The strophe begins abruptly. In a rapid crescendo, the abdomen oscillating faster and faster, it acquires its maximum volume; it keeps up the same degree of strength for a few seconds and then becomes gradually weaker and degenerates into a tremolo which decreases as the belly relapses into rest. With the last pulsations of the abdomen comes silence, which lasts for a longer or shorter time according to the condition of the atmosphere. Then suddenly we hear a new strophe, a monotonous repetition of the first; and so on indefinitely.

It often happens, especially during the sultry evening hours, that the insect, drunk with sunshine, shortens and even entirely suppresses the pauses. The song is then continuous, but always with alternations of crescendo and decrescendo. The first strokes of the bow are given at about seven or eight o’clock in the morning; and the orchestra ceases only with the dying gleams of the twilight, at about eight o’clock in the evening. Altogether the concert lasts the whole round of the clock. But, if the sky be overcast, if the wind blow cold, the Cicada is dumb.

The second species is only half the size [66]of the Common Cicada and is known in the district by the name of the Cacan, a fairly accurate imitation of his peculiar rattle. This is the Ash Cicada of the naturalists; and he is far more alert and more suspicious than the first. His harsh loud song consists of a series of Can! Can! Can! Can! with not a pause to divide the ode into strophes. Its monotony and its harsh shrillness make it a most unpleasant ditty, especially when the orchestra is composed of some hundreds of executants, as happens in my two plane-trees during the dog-days. At such times it is as though a heap of dry walnuts were being shaken in a bag until the shells cracked. This irritating concert, a veritable torment, has only one slight advantage about it: the Ash Cicada does not start quite so early in the morning as the Common Cicada and does not sit up so late at night.

Although constructed on the same fundamental principles, the vocal apparatus displays numerous peculiarities which give the song its special character. The sound-chamber is entirely lacking, which means that there is no entrance-window either. The cymbal is uncovered, just behind the insertion of the hind-wing. It again is a dry, white [67]scale, convex on the outside and crossed by a bundle of five red-brown nervures.

The first segment of the abdomen thrusts forward a short, wide tongue, which is quite rigid and of which the free end rests on the cymbal. This tongue may be compared with the blade of a rattle which, instead of fitting into the teeth of a revolving wheel, touches the nervures of the vibrating cymbal more or less closely. The harsh, grating sound must, I think, be partly due to this. It is hardly possible to verify the fact when holding the creature in our fingers: the startled Cacan does anything at such times rather than emit his normal song.

The lids do not overlap; on the contrary, they are separated by a rather wide interval. With the rigid tongues, those appendages of the abdomen, they shelter one half of the cymbals, the other half of which is quite bare. The abdomen, when pressed with the finger, does not open to any great extent where it joins the thorax. For the rest, the insect keeps still when it sings; it knows nothing of the rapid quivering of the belly that modulates the song of the Common Cicada. The chapels are very small and almost negligible as sounding-boards. There [68]are mirrors, it is true, but insignificant ones, measuring scarcely a twenty-fifth of an inch. In short, the mechanism of sound, which is so highly developed in the Common Cicada, is very rudimentary here. How then does the thin clash of the cymbals manage to gain in volume until it becomes intolerable?

The Ash Cicada is a ventriloquist. If we examine the abdomen by holding it up to the light, we see that the front two thirds are translucent. Let us snip off the opaque third part that retains, reduced to the strictly indispensable, the organs essential to the propagation of the species and the preservation of the individual. The rest of the belly is wide open and presents a spacious cavity, with nothing but its tegumentary walls, except in the case of the dorsal surface, which is lined with a thin layer of muscle and serves as a support to the slender digestive tube, which is little more than a thread. The large receptacle, forming nearly half of the insect’s total bulk, is therefore empty, or nearly so. At the back are seen the two motor pillars of the cymbals, the two muscular columns arranged in a V. To the right and left of the point of this V gleam the two tiny mirrors; and the empty space is [69]continued between the two branches into the depths of the thorax.

This hollow belly and its thoracic complement form an enormous resonator, unapproached by that of any other performer in our district. If I close with my finger the orifice in the abdomen which I have just clipped, the sound becomes lower, in conformity with the laws affecting organ-pipes; if I fit a cylinder, a screw of paper, to the mouth of the open belly, the sound becomes louder as well as deeper. With a paper funnel properly adjusted, its wide end thrust into the mouth of a test-tube acting as a sounding-board, we have no longer the shrilling of the Cicada but something very near the bellowing of a Bull. My small children, happening to be there at the moment when I am making my acoustic experiments, run away scared. The familiar insect inspires them with terror.

The harshness of the sound appears to be due to the tongue of the rattle rasping the nervures of the vibrating cymbals; its intensity may no doubt be ascribed to the spacious sounding-board of the belly. Assuredly one must be passionately enamoured of song thus to empty one’s belly and chest in order [70]to make room for a musical-box. The essential vital organs are reduced to the minimum, are confined to a tiny corner, so as to leave a greater space for the sounding-cavity. Song comes first; all the rest takes second place.

It is a good thing that the Ash Cicada does not follow the teaching of the evolutionists. If, becoming more enthusiastic from generation to generation, he were able by progressive stages to acquire a ventral sounding-board fit to compare with that which my paper screws give him, my Provence, peopled as it is with Cacans, would one day become uninhabitable.

After the details which I have already given concerning the Common Cicada, it seems hardly necessary to say how the insupportable chatterbox of the Ash is rendered dumb. The cymbals are clearly visible on the outside. You prick them with the point of a needle. Complete silence follows instantly. Why are there not in my plane-trees, among the dagger-wearing insects, auxiliaries who, like myself, love quiet and who would devote themselves to that task! A mad wish! A note would then be lacking in the majestic harvest symphony.[71]

The Red Cicada (C. hematodes) is a little smaller than the Common Cicada. He owes his name to the blood-red colour that takes the place of the other’s brown on the veins of the wings and some other lineaments of the body. He is rare. I come upon him occasionally in the hawthorn-bushes. As regards his musical apparatus, he stands half-way between the Common Cicada and the Ash Cicada. He has the former’s oscillation of the belly, which increases or reduces the strength of the sound by opening or closing the church; he possesses the latter’s exposed cymbals, unaccompanied by any sound-chamber or window.

The cymbals therefore are bare, immediately after the attachment of the hind-wings. They are white, fairly regular in their convexity and boast eight long, parallel nervures of a ruddy brown and seven others which are much shorter and which are inserted singly in the intervals between the first. The lids are small and scolloped at their inner edge so as to cover only half of the corresponding chapel. The opening left by the hollow in the lid has as a shutter a little pallet fixed to the base of the hind-leg, which, by folding itself against the body or lifting slightly, [72]keeps the aperture either shut or open. The other Cicadæ have each a similar appendage, but in their case it is narrower and more pointed.

Moreover, as with the Common Cicada, the belly moves freely up and down. This heaving movement, combined with the play of the femoral pallets, opens and closes the chapels to varying extents.

The mirrors, though not so large as the Common Cicada’s, have the same appearance. The membrane that faces them on the thorax side is white, oval and very delicate and is tight-stretched when the abdomen is raised and flabby and wrinkled when the abdomen is lowered. In its tense state it seems capable of vibration and of increasing the sound.

The song, modulated and subdivided into strophes, suggests that of the Common Cicada, but is much less objectionable. Its lack of shrillness may well be due to the absence of any sound-chambers. Other things being equal, cymbals vibrating uncovered cannot possess the same intensity of sound as those vibrating at the far end of an echoing vestibule. The noisy Ash Cicada also, it is true, lacks that vestibule; but he [73]amply makes up for its absence by the enormous resonator of his belly.

I have never seen the third Cicada, sketched by Réaumur and described by Olivier1 under the name of C. tomentosa. The species is known in Provence, so this and that one tells me, by the name of the Cigalon, or rather Cigaloun, the Little Cigale or Cicada. This designation is unknown in my neighbourhood.

I possess two other specimens which Réaumur probably confused with the one of which he gives us a drawing. One is the Black Cicada (C. atra, Oliv.), whom I came across only once; the other is the Pigmy Cicada (C. pygmæa, Oliv.), whom I have picked up pretty often. I will say a few words about this last one.

He is the smallest member of the genus in my district, the size of an average Gad-fly, and measures about three-quarters of an inch in length. His cymbals are transparent, with three opaque veins, are scarcely sheltered by [74]a fold in the skin and are in full view, without any sort of entrance-lobby or sound-chamber. I may remark, in terminating our survey, that the entrance-lobby exists only in the Common Cicada; all the others are without it.

The dampers are separated by a wide interval and allow the chapels to open wide. The mirrors are comparatively large. Their shape suggests the outline of a kidney-bean. The abdomen does not heave when the insect sings; it remains stationary, like the Ash Cicada’s. Hence a lack of variety in the melody of both.

The Pigmy Cicada’s song is a monotonous rattle, pitched in a shrill key, but faint and hardly perceptible a few steps away in the calm of our enervating July afternoons. If ever a fancy seized him to forsake his sun-scorched bushes and to come and settle down in force in my cool plane-trees—and I wish that he would, for I should much like to study him more closely—this pretty little Cicada would not disturb my solitude as the frenzied Cacan does.

We have now ploughed our way through the descriptive part; we know the instrument of sound so far as its structure is concerned. [75]In conclusion, let us ask ourselves the object of these musical orgies. What is the use of all this noise? One reply is bound to come: it is the call of the males summoning their mates; it is the lovers’ cantata.

I will allow myself to discuss this answer, which is certainly a very natural one. For fifteen years the Common Cicada and his shrill associate, the Cacan, have thrust their society upon me. Every summer for two months I have them before my eyes, I have them in my ears. Though I may not listen to them gladly, I observe them with a certain zeal. I see them ranged in rows on the smooth bark of the plane-trees, all with their heads upwards, both sexes interspersed with a few inches between them.

With their suckers driven into the tree, they drink, motionless. As the sun turns and moves the shadow, they also turn around the branch with slow lateral steps and make for the best-lighted and hottest surface. Whether they be working their suckers or moving their quarters, they never cease singing.

Are we to take the endless cantilena for a passionate call? I am not sure. In the assembly the two sexes are side by side; and [76]you do not spend months on end in calling to some one who is at your elbow. Then again, I never see a female come rushing into the midst of the very noisiest orchestra. Sight is enough as a prelude to marriage here, for it is excellent; the wooer has no use for an everlasting declaration: the wooed is his next-door neighbour.

Could it be a means then of charming, of touching the indifferent one? I still have my doubts. I notice no signs of satisfaction in the females; I do not see them give the least flutter nor sway from side to side, though the lovers clash their cymbals never so loudly.

My neighbours the peasants say that, at harvest-time, the Cicada sings, “Sego, sego, sego! Reap, reap, reap!” to encourage them to work. Whether harvesters of wheat or harvesters of thought, we follow the same occupation, one for the bread of the stomach, the other for the bread of the mind. I can understand their explanation, therefore; and I accept it as an instance of charming simplicity.

Science asks for something better; but she finds in the insect a world that is closed to us. There is no possibility of divining or even [77]suspecting the impression produced by the clash of the cymbals upon those who inspire it. All that I can say is that their impassive exterior seems to denote complete indifference. Let us not insist too much: the private feelings of animals are an unfathomable mystery.

Another reason for doubt is this: those who are sensitive to music always have delicate hearing; and this hearing, a watchful sentinel, should give warning of any danger at the least sound. The birds, those skilled songsters, have an exquisitely fine sense of hearing. Should a leaf stir in the branches, should two wayfarers exchange a word, they will be suddenly silent, anxious, on their guard. How far the Cicada is from such sensibility!

He has very clear sight. His large faceted eyes inform him of what happens on the right and what happens on the left; his three stemmata, like little ruby telescopes, explore the expanse above his head. The moment he sees us coming, he is silent and flies away. But place yourself behind the branch on which he is singing, arrange so that you are not within reach of the five visual organs; and then talk, whistle, clap [78]your hands, knock two stones together. For much less than this, a bird, though it would not see you, would interrupt its singing and fly away terrified. The imperturbable Cicada goes on rattling as though nothing were afoot.

Of my experiments in this matter, I will mention only one, the most memorable. I borrow the municipal artillery, that is to say, the mortars which are made to thunder forth on the feast of the patron-saint. The gunner is delighted to load them for the benefit of the Cicadæ and to come and fire them off at my place. There are two of them, crammed as though for the most solemn rejoicings. No politician making the circuit of his constituency in search of re-election was ever honoured with so much powder. We are careful to leave the windows open, to save the panes from breaking. The two thundering engines are set at the foot of the plane-trees in front of my door. No precautions are taken to mask them: the Cicadæ singing in the branches overhead cannot see what is happening below.

We are an audience of six. We wait for a moment of comparative quiet. The number [79]of singers is checked by each of us, as are the depth and rhythm of the song. We are now ready, with ears pricked up to hear what will happen in the aerial orchestra. The mortar is let off, with a noise like a genuine thunder-clap.

There is no excitement whatever up above. The number of executants is the same, the rhythm is the same, the volume of sound the same. The six witnesses are unanimous: the mighty explosion has in no way affected the song of the Cicadæ. And the second mortar gives an exactly similar result.

What conclusion are we to draw from this persistence of the orchestra, which is not at all surprised or put out by the firing of a gun? Am I to infer from it that the Cicada is deaf? I will certainly not venture so far as that; but, if any one else, more daring than I, were to make the assertion, I should really not know what arguments to employ in contradicting him. I should be obliged at least to concede that the Cicada is extremely hard of hearing and that we may apply to him the familiar saying, to bawl like a deaf man.

When the Blue-winged Locust takes his luxurious fill of sunshine on a gravelly path [80]and with his great hind-shanks rubs the rough edge of his wing-cases; when the Green Tree-frog, suffering from as chronic a cold as the Cacan, swells his throat among the leaves and distends it into a resounding bladder at the approach of a storm, are they both calling to their absent mates? By no means. The bow-strokes of the first produce hardly a perceptible stridulation; the throaty exuberance of the second is no more effective: the object of their desire does not come.

Does the insect need these sonorous outbursts, these loquacious avowals, to declare its flame? Consult the vast majority, whom the meeting of the two sexes leaves silent. I see in the Grasshopper’s fiddle, the Tree-frog’s bagpipes and the cymbals of the Cacan but so many methods of expressing the joy of living, the universal joy which every animal species celebrates after its kind.

If any one were to tell me that the Cicadæ strum on their noisy instruments without giving a thought to the sound produced and for the sheer pleasure of feeling themselves alive, just as we rub our hands in a moment of satisfaction, I should not be greatly [81]shocked. That there may be also a secondary object in their concert, an object in which the dumb sex is interested, is quite possible, quite natural, though this has not yet been proved.