Locusts and _locustidæ_—The most musical grasshoppers—Katydid
concerts—A much-resembling note—Cricket thermometers—Cicadas
and sounding-boards—Admired musicians—An appreciative
audience.
LOCUSTS, as everybody knows, belong to the grasshopper family, but it
may surprise some who have read the grumblings of the learned over
popular names—white ants, hedge-sparrows, etc.—to find that
entomologists have so managed matters that they do not belong to the
_locustidæ_—which is one of the two groups into which all grasshoppers
are divided—but to the other group. There are long-horned grasshoppers
and short-horned grasshoppers. The long-horned ones, which are not
locusts, are all of them _locustidæ_, but none of the _locustidæ_ are
locusts, because locusts have short horns. Entomologists think it would
be absurd to alter this, after it has gone on so long, a view in which
ornithologists, with their _storm_-petrels and hedge-_accentors_, no
doubt agree with them. A mere popular name, with its roots in the Saxon
or Celtic, can be changed, and there an end, but scientific nonsense, in
Latin, and begun by Linnæus, as is generally the case, let no man
presume to meddle with.
It is amongst the _locustidæ_ that we find the most musical of the
grasshoppers, the Katydids—so well known and highly appreciated in the
United States—standing on a far higher level in this respect than the
comparatively unmusical locusts. Not that the _locustidæ_—however
musical—use their long horns for blowing purposes. Properly speaking,
these are only antennæ, and function as such, the musical apparatus
being situated elsewhere. The Katydids, for instance, rasp their fore
wings against each other, according to the general idea, three times in
succession, producing the three syllables, Ka—ty—did, which have given
the insect its name, but according to Mr. Scudder[25] only twice, which
makes either “Katy,” or “She did”; that is to say, as a general rule,
for he admits the three on occasions. The notes are uttered with great
emphasis, and at the rate of some two hundred in the minute, the
performance continuing, at least in the case of some species, all day
and all night long.
A number of grasshoppers go by the name of Katydids in America, but the
general type of the insect is a graceful, green, fragile-looking
creature, with very long, slender antennæ, and, in the female, a long
ovipositor at the other end, as if to balance matters. There are many
species, and all, or most of them, sing both by night and day, and what
is very remarkable, or, at least, very interesting, they have a
different note for either. Speaking of one—or, rather, of a long-horned
grasshopper nearly related to the Katydids, but not actually a member of
the sisterhood—which he had been watching in the sunshine, Mr. Scudder
says: “As a cloud passed over the sun he suddenly changed his note to
one with which I was already familiar, but without knowing to what
insect it belonged. At the same time, all the individuals around, whose
similar day-song I had heard, began to respond with the night-cry. The
cloud passed away, and the original note was resumed on all sides.”[26]
_Scudderia angustifolia_ is the name of this little musician, so called,
perhaps, because so sensitive to scudding clouds. But the Katydids do
more than merely play an individual tune, each on his own instrument.
They hold concerts, at which many join together to make an elaborate
musical display, a certain number commencing on one note, and others
joining in harmoniously on another. There are leaders, whose business it
is to hold the time-measure, and, by a steady insistence on the right
note, to draw back any who may happen for a moment to get out of tune.
The orchestra is divided into so many companies, who support and assist
one another, so that the whole makes a concerted harmony, in which there
are many different movements. As a rule the performance is most
creditable, though occasionally the effect is marred by a careless
player. Before commencing, the company always tunes up.
Possibly it may be thought that there is some mistake here—that things
cannot be quite like this. Personally I have no knowledge on the
subject—never having been to America—but here is what Dr. George M.
Gould says, writing in _Science_ for October or November, probably 1895,
since the number is referred to as “recent” in _Nature_ for December 5th
of that year. “As soon as the sun has set and twilight is advancing, the
Katydids in the trees begin to ‘tune up.’ The first notes are scattered,
awkward and without rhythm, but if no wind is blowing thousands soon
join in, and from time to time, until daylight breaks, there is no
intermission.... In order to make my description clearer, let us suppose
a thousand Katydids, scattered through the trees, to utter their several
notes all at once, and call them Company A. Another thousand—Company
B—at once answers them, and this swing-swong is kept up, as I say, all
night. Company A’s note is the emphatic or accented note, and is more
definitely and accurately a precise musical note, whilst the note of
Company B varies from one to five half-tones below, the most conspicuous
note being five. In the old-fashioned musical terms I learned as a boy,
Company A is, e.g., clearly and definitely _do_, while the note of
Company B is either _la_, or more certainly _sol_. Not only is Company
A’s note more unisonal and definite, but it is firmer, more accented,
and it seems to me that more insects join in this note than in the
second. Careful observation has convinced me that no insect of Company A
or Company B ever joins in the other company’s note. The rhythm is
usually perfect, unless there is a disturbance by a breeze. A sharp gust
upsets the whole orchestra, and confusion results, but the measured beat
is soon refound. In the instants of confusion one can detect the steady
see-saw of certain ones, as it were, ‘leaders,’ or first violinists, who
hold the time-measure, despite the wind, and who soon draw the lost
notes of the others once more into the regular measure or beat. I do not
mean to say that by diligent attention one may not at times detect
individuals sawing out of tune, stray fellows that are indifferent or
careless, but the vast majority, usually even without a single
exception, if there is no wind or rain, thus swing along, hour after
hour, in perfect time. I have counted the beats several times, and find
the number is always identical: thirty-four double beats, or sixty-eight
single ones, in sixty seconds. The effect of the rhythm upon the mind is
not unlike that of the woodman’s cross-cut saw, handled by two steady,
tireless pairs of hands, although the Katydids give a larger volume of
sound, and the _timbre_ is harsher.” Such is the account, and upon it
Dr. Gould asks two questions: “What function does the orchestration
subserve?” and “Is there anything comparable to it among other animals?”
In view of these performances of the Katydids one may perhaps question
the statement, often made, that crickets are _the_ most musical of all
insects. The Snowy Cricket, however, of the United States, and no doubt
elsewhere in America, is a very striking performer, especially at night,
when it emits sounds which Nathaniel Hawthorne has likened to “audible
stillness,” and of which he says: “If moonlight could be heard it would
sound like that.” Thoreau describes it as a “slumbrous breathing,” but
according to the State Entomologist of the United States, this
“slumbrous breathing,” or “audible stillness,” consists of “a shrill
re-teat, re-teat, re-teat,” which Mr. Leland Howard,[26] indeed, thinks
the best description, but is not quite my idea—nor probably
Hawthorne’s—of how moonlight would sound. Harrington—who I suppose is
another entomologist—does not interfere with any of these opinions, but
describes something which he has seen, and can find nothing about in
books. “While the male,” he says, “is energetically shuffling together
his wings, raised almost vertically, the female may be seen standing
just behind him, and with her head applied to the base of the wings,
evidently eager to get the full benefit of every note produced.”[26] No
doubt the female likes the notes—that, indeed, is the _rationale_ of
their utterance—but what they are really like it is impossible to make
out from these various descriptions, another of which, by the way, is “a
rhythmic beat.” Possibly they are no more extraordinary (at any rate,
“re-teat” is not) than those of our own, and cheerful, house-cricket,
which to my ear have always sounded very pretty, but which Cowper
evidently did not care about except as a matter of association, since he
thus alludes to them in the _Task_:—
“Sounds inharmonious in themselves and harsh,
Yet heard in scenes where peace for ever (sic) reigns,
And only there, please highly for their sake.”
No doubt there are associations, though these, belonging to the kitchen,
appear to me to be of another and blither description, but the “sounds”
themselves, in my opinion, are neither harsh nor inharmonious, as far as
any unpleasantness to the ear is conveyed by the last word.
One interesting point about the song of crickets is that the number of
notes uttered in any given space of time—per minute, say—varies
according to the temperature, the two rising together. Professor
Dolbeare was the first, as far as I know, to call attention to this
fact, and he is thus confirmed by a lady: “One cool evening a cricket
was caught and brought into a warm room. In a few minutes it began to
chirp nearly twice as rapidly as the out-of-door crickets. Its rate very
nearly conformed to the observed rate maintained on other evenings under
the same temperature conditions (as now indoors). From this series of
observations we found that the rate of chirping was, as Professor
Dolbeare says, very closely dependent on the temperature.”[27] So the
crickets are little thermometers—sixty-three degrees Fahrenheit to one
hundred chirps per minute.
As we have seen, the Katydids give concerts, and we may therefore infer
that they like their own music in a musically appreciative way; that
they listen to each other as critical connoisseurs, whether they have
other feelings or not, and that it is not a mere matter of the female
alone admiring the sounds made by the male, just because _he_ makes
them. In all this, however, the admiration is confined—at least, as far
as we know—to one species—that to which the musician belongs. Katydids
appreciate the performances of Katydids. But there is one group of
performers whose music gives satisfaction, not merely to individuals of
other species than their own, but to such as are not even included in
the same order with them, so that racial pride or family prejudice
cannot be the reason of it. Towards these stars we will now turn our
gaze.
All who have lived in the more southern parts of the world, including
the southern countries of Europe, must have made the acquaintance of the
cicadas, for in these regions they are large insects, conspicuous by
their appearance when once seen, and by their song long before they are
noticed. There is something very uncouth—one might almost say
grotesquely humorous—yet at the same time pleasing and lovable about the
broad flat heads and great goggle eyes of these insects, in the which it
is easy to imagine some quaint sort of expression that seems to mean or
suggest something for which the language supplies no word. Their wings,
both long and broad, which, when folded, project far beyond the
extremity of the abdomen, concealing everything save the great head and
the wide shield or boss of the thorax, help also in giving them a most
salient and characteristic appearance, and make them look more aerial
than they really are. Their legs, whilst they retain their ordinary
resting attitude, are entirely hidden, and so too are the organs of the
mouth, which combine to make a sharp-pointed beak. Thus their appearance
is typical of air and sunshine, and anything so gross as mere feeding or
terrestrial locomotion seems foreign to their nature. The ancients, who
loved and admired the cicadas extremely, thinking them the most
fortunate of creatures, supposed that they lived entirely on dew.
“Oh Tettix, drunk with sipping dew,
What musician equals you?”
sings Anacreon, or someone who imitated him and wrote very gracefully,
for Tettix was a common Greek name for the cicada. Really they live on
the sap of the trees on which they sit, and there may even be two
opinions about their music. To me it is pleasant enough—full of the joy
of the sunshine, as it were, and its loudness and the continuous way in
which it goes on excites one’s wonder. In regard to the way in which it
is produced, Darwin says, at page 351 of his immortal work, _The Descent
of Man_: “The sound, according to Laudois, who has recently studied the
subject, is produced by the vibration of the lips of the spiracles,
which are set in motion by a current of air emitted by the tracheæ. It
is increased by a wonderfully complex resounding apparatus, consisting
of two cavities covered with scales. Hence the sound may truly be called
a voice. In the female the musical apparatus is present, but very much
less developed than in the male, and is never used for producing sound.”
As the Greeks, who must have had their observers, used to say—
“Happy the cicadas’ lives,
Since they all have voiceless wives.”
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.
-----
Footnote 25:
Leland O. Howard, The Insect Book. It has, however, been asserted, I
know not with what truth, that Mr. Scudder was mistaken in this
particular, and changed his opinion.
Footnote 26:
Leland O. Howard, The Insect Book.
Footnote 27:
The American Naturalist, April, 1898.
Footnote 28:
Transactions of the New Zealand Institute, vol. 5, p. 286.
Footnote 29:
Proceedings of the Zoological Society for 1900, pp. 837-69.
Footnote 30:
Transactions of the New Zealand Institute, vol. 5, p. 286.
Footnote 31:
Nature, vol. 44, p. 451.
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