This sounds all right—I mean the account of the apparatus—but according to Dr. Powell, of New Zealand, it is all wrong. Writing in the Transactions of the New Zealand Institute,[[28]] Dr. Powell, after quoting the above passage, says, “I am, of course, ignorant of the details of his description; but unless the cicada which he describes differs essentially in the nature of its musical organs from those found in New Zealand, and also from those described more or less correctly by other authors, especially Réaumur, he is most certainly in error.” Dr. Powell, then, after telling us that the stridulating organs of the cicada are constructed on a principle unique in nature, viz. a vibrating membrane, continues: “In the male, on the upper surface of the first ring of the abdomen, on either side, may be seen a crescent-shaped opening, and on examining this opening with a magnifying-glass it will be seen to lead into a shallow cavity, closed in by a horny membrane. This membrane is highly elastic, and the sound is produced by the contraction of the muscle straightening out the folds of the membrane; this produces a click and, on the muscle relaxing, the membrane, from its elasticity, springs back with another click.” That this is really the way in which the sounds are produced seems proved by the fact that “if a live insect be caught, and these membranes be observed during the act of stridulation, they will be seen to be vibrating rapidly in time with the beats of the shrill sound.”
But what about the “wonderfully complex resounding apparatus, consisting of two cavities covered with scales”? After a full examination and various experiments, Dr. Powell arrives at the unexpected conclusion that the sound is in no way dependent upon these “large transparent, drum-like membranes,” as he calls the cavities in question. I was “much surprised,” he says, “to find that the large drums seemed to take no part in the production of the sound, and the idea occurred to me that they might be hearing organs; but on examining the females, which are dumb and do not possess the stridulating organs, I found that the drums exist, indeed, but are quite rudimentary instead of being large, as we should expect to find them, were they subservient to the sense of hearing.” If, however, the drums did answer the purpose of a resounding apparatus in the male, we should expect to find them exactly as they are in the female, and so strong does the evidence of their suppression in her appear to me, that I cannot help thinking that, in spite of all Dr. Powell’s observations and experiments, he was somehow mistaken, and that in nature they do act in this way.
As to the quality of the sound produced by the cicada—of its song, as we may call it—this varies greatly in the different species, for there are many cicadas. Speaking of that of the largest—the great Pomponia imperatoria of Borneo—as big as a mouse, one may almost say, Mr. Annandale remarks, “The sound produced by this species is, at the beginning of the song, like the winding up of a large clock, and ends by being comparable to the notes of a penny whistle. Between these extremes it rises in a series of trills, each of which concludes with a kind of click. Each section of the song is faster, louder, and clearer than the one which preceded it, until, almost five minutes after the cicada’s settling, the noise suddenly comes to an end as the insect flies off to another tree, where it commences again.”[[29]] This great pompous imperial insect—to give it a free rendering of its Latin name—sits shrouded in the mysteries of the deeper jungle, while smaller and less majestic babblers haunt its skirtings and the village groves. “Another species, commonly heard at night in the jungle, has a clear, loud, clarion-like call, which can be heard for a great distance.”[[29]]
Of the three New Zealand species of cicada—or those found in Canterbury—a large and small green, and a black one, the two first, Dr. Powell tells us, say “crrrk-crrrk-crrrk,” the second “r-r-r-r-r-r,” and the third “crrrk-rrrrr,” ad infinitum. “Many persons,” he adds, “are totally unable to hear the voice of the small green cicada, or any very acute sounds, and inasmuch as the entire range of the human ear is, according to Helmholtz, eleven octaves, it has been justly remarked that the air may be filled with shrill insect sounds, which may be perfectly audible to the insects themselves, but absolutely inaudible to our grosser senses.”[[30]]
It is in Natal—at least, the fact has been observed there—that the cicadas, as they sing, are listened to by admiring groups of other insects. These appear to be beautiful creatures, having wings of a soft, gauzy texture, but iridescent, and shot with the colours of the rainbow. A band of these radiant attendants, consisting sometimes of a dozen or fifteen, fly to the tree where a cicada is sitting and arrange themselves in a semicircle around it, facing its head. They are “all ear” evidently, and, as the sweet sounds continue, one or other of the listeners will advance and touch the antennæ or legs of the object of its admiration. Such marks of appreciation, however, though flattering in proportion to their undoubted sincerity, are not to the taste of the cicada, who will sometimes, whilst in the midst of its song, strike out vigorously with a foot or so—for, of course, it has six—causing its too obtrusive admirers to retreat to a more respectful distance, where they continue to listen with every sign of being extremely pleased.[[31]] Some years ago we did not even know the name of these musical-connoisseur-like, and withal very beautiful insects, but now they have been identified by Mr. Kirby, at the British Museum, as Nothochrysa gigantea, so we are all much the wiser, and have a weight lifted from our minds.
CHAPTER IX
A Greek mistake—Nature vindicated—Cicadas provided for—A difficult feat—Perseverance rewarded—Cicadas in story—Dear to Apollo—Men before the Muses—Plato and Socrates—Athenian views—A mausoleum for pets—The Greek ploughman—Apollo’s judgment—Hercules’ bad taste—Modern survivals—A beneficent insect—Elementary education in Tuscany.
THE Greeks thought that the life of the cicadas was all joy, but modern research has been successful in removing the reproach of inconsistency from the general scheme of creation. All is in order, as it now appears: the cicada’s case has been considered, and a very handsome wasp provided for it. At least, I think it is handsome. It is large and strong, I know, as is necessary for the part it has to perform, but I cannot quite remember the colours it flies under; an expression which, though metaphorical, may be pardoned, since flags have much to do with such dramas as that now to be described. For as the joyous, sun-loving creature sits in its accustomed place, chirupping forth those shrill yet musical notes which I, at least, have never wearied of, the destroyer is at hand, and settling on its broad back, curves its abdomen beneath that of the poor blithe singer, and in a moment has done its work. As the sting enters, the happy note that has been sounding regularly for the last hour, perhaps, is changed to a discordant scream of pain, and with a spasmodic spring or flutter—the last, or near the last, that it will ever make—the cicada, with the wasp still clinging to it, falls to the ground. This is awkward for the wasp, who doubtless considers herself aggrieved in the matter, since the cicada is so bulky that, powerful as she is, she can neither lift it from the ground in flight, nor is she prepared to drag it all the way to her burrow. What, then, is she to do, or of what use to her is the prize she has obtained with such adroitness? But she has her plan, and though the captious behaviour of the cicada has, for the moment, a little deranged it, it is not permanently frustrated. Slowly, but with firm insistence, she drags her victim to the tree on which a moment before it was so happily seated, and then exerting all her force, begins to mount the trunk with it. Often she has to pause and rest, often it seems as though the task would be beyond her, but she continues the laborious ascent, sometimes for upwards of an hour, until at last a height has been reached at which it is possible for her to put her great project into execution. This is no other than to fly down obliquely, with her victim clasped in her arms, to the pleasant little sarcophagus which she has previously prepared for it, for though flight upwards, or in a straight line, with such a burden, is out of the question, her strength is equal to this. It is necessary, however, that she should balance the body nicely, and make a fair and uninterrupted start, in order not to be overweighted and again fall. Her enterprise is “full of poise and difficult weight,” and cannot be successfully carried out in face of the rude struggles of a tiresome obstructive not “in tune with the infinite.” These struggles, however, have now ceased; the cicada is in a comatose condition, and, having adjusted it properly, and assumed the requisite attitude and position, our wasp—whose scientific name, by the way, is Sphecius speciosus—launches herself, with “the white man’s burden” she has “taken up,” from her coign of vantage, and reaches home with it in safety. How high she has previously ascended the tree I cannot say, since my informant does not, but it would be interesting to ascertain both this and the average distance which she has to fly to her nest, and to compare the one with the other. Unless the latter is very much greater than the former—and as the journey is constantly downwards it cannot, one would think, be very far—then we must see in the wasp’s choice of a toilsome ascent up a perpendicular tree-trunk, in preference to a horizontal journey along the ground, a triumph of instinct over intelligence, and it is, indeed, quite possible that, having always been accustomed to fly back with her prize, which perhaps was not always so heavy, she should go through as much labour to enable her to do this as, differently directed, would attain the end for which it is employed.