lizard that walks against gravity. St. Pierre mentions one not longer
than a finger, that, in the Isle of France, climbs along the walls,
and even up the glass after the flies and other insects, for which
it watches with great patience. These lizards are sometimes so tame
that they will feed out of the hand.--_Voyage_, &c. 73. Major Moor
and Captain Green observed similar lizards in India, that ran up the
walls and over the ceilings after the mosquitos. Hasselquist says
that the Gecko is very frequent at Cairo, both in the houses and
without them, and that it exhales a very deleterious poison from the
lobuli between the toes. He saw two women and a girl at the point
of death, merely from eating a cheese on which it had dropped its
venom. One ran over the hand of a man, who endeavoured to catch
it; and immediately little pustules, resembling those occasioned
by the stinging-nettle, rose all over the parts the creature had
touched.--_Voyage_, 220. M. Savigny, however, who examined this
animal in Egypt, assures me that this account of Hasselquist's, as
far as it relates to the venom of the Gecko, is not correct.
[502] _Philos. Trans._ 1816. 325. _t._ xviii. _f._ 1-7.
[503] Ibid. _f._ 8-11.
[504] Kirby in _Linn. Trans._ xi. 106. _t._ viii. _f._ 13. _a._
[505] I observed this in the hind legs of a variety of _Locusta
migratoria_.
[506] _Philos. Trans._ 1816. _t._ xix. _f._ 5.
[507] Ibid. p. 325.
[508] In a specimen in my cabinet of _Blatta gigantea_, the posterior
and anterior tarsi of one side have only four joints, while the
intermediate one has five. On the other side the hind leg is broken
off, but the anterior and intermediate tarsi have both five joints.
In another specimen one posterior tarsus has four and the other five
joints.
[509] The name of this genus properly spelled is _Troxallis_, from
the Greek Τρωξαλλις, _Gryllus_.
[510] This insect, which is remarkable for having the margin of its
thorax reflexed, was long since well figured in Mouffet's work (130.
_fig. infima_). It has not, however, been described by any other
author I have met with. It is common in Brazil. Some specimens are
pallid, while others are of a dark brown. It is to be observed that
the _Blattina_ are resolvable into several genera.
[511] De Geer, iii. 421. _t._ xxi. _f._ 13. _h._ This author has also
noticed the cushions in this genus and _Locusta_, and the claw-sucker
in the latter, which he thinks are analogous to those of the fly.
_Ibid._ 462-- _t._ xxii. _f._ 7-8.
[512] _Philos. Trans._ 1816. _t._ xxi. _f._ 8-13.
[513] See _Zoolog. Jour._ for 1825. No. iv. 431.
[514] _Philos. Trans._ 1816. _t._ xxi. _f._ 1-9.
[515] The orthography of this name is _Troxallis_, from the Greek
Τρωξαλλις, _Gryllus_.
[516] De Geer, iii. 132. 173.
[517] De Geer, iii. 7.
[518] _Philos. Trans._ 1816. _t._ xix. _f._ 3, 4.
[519] Ibid. _t._ xix. _f._ 1-9.
[520] De Geer, vii. 91. _t._ v. _f._ 6, 7.
[521] Ibid. 96-- _t._ v. _f._ 13, 14, 17, 19. _t._ vi. _f._ 2. 5.
[522] VOL. I. 405--.
[523] 65.
[524] _Microgr._ 202. It has been objected to an excellent primitive
writer (_Clemens Romanus_), that he believed the absurd fable of
the phœnix. But surely this may be allowed for in him, who was no
naturalist, when a scientific natural philosopher could believe that
the clouds are made of spiders web!
[525] Latreille, _Hist. Nat._ xii. 388.
[526] Quoted in the _Athenæum_, v. 126.
[527] Ray's _Letters_, 69. 36--.
[528] Ray's _Letters_, 37. 87. Lister _De Aran._ 80. Lister
illustrates the force with which these creatures shoot their thread,
by a homely though very forcible simile: "Resupinata (says he) anum
in ventum dedit, filumque ejaculata est quo plane modo robustissimus
juvenise distentissima vesicâ urinam."
[529] _De Araneis_, 8. 27. 64. 75-- 79--.
[530] Ibid. 79--.
[531] Ibid. 85.
[532] _Nat. Hist._ i. 327.
[533] No. lii. 306--.
[534] Cuvier, _Anat. Comp._ i. 504.
[535] _Nat. Hist._ i. 325--.
[536] _Neue Schriften der Naturforschenden Gessellschaft zu Halle_
1810. v. _Heft_.
[537] _Nat. Hist._ i. 326.
[538] Ray's _Letters_, 36.
[539] Ibid. 42. Lister _De Araneis_, 8.
[540] VOL. I. 113--.
[541] Lichtenberg und Voight _Magazin_, 1789. vi. 53--.
[542] _Neue Schriften der Naturforsch_. &c. 1810. v. _Heft_, 41-56.
[543] _De Araneis_, 66.
[544] Ibid. 79.
[545] _Nat. Hist._ i. 326.
[546] Swamm. _Bibl. Nat._ Ed. Hill, i. 24. De Geer, vii. 190.
[547] French naturalists use this term (_nervure_) for the veins of
wings, leaves, &c. restricting _nerve_ (_nerf_) to the ramifications
from the brain and spinal marrow. We have adopted the term, which we
express in Latin by _neura_, from the Greek νευρα.
[548] Jurine _Hymenopt._ 19.
[549] PLATE X. FIG. 1.
[550] PLATE XXIII. FIG. 6. _e´´´._
[551] PLATE X. FIG. 4.
[552] In PLATE XXIII. FIG. 5. the wings of _Dytiscus marginalis_ are
represented as they appear when folded.
[553] _Entomol._ i. 1.
[554] PLATE X. FIG. 5.
[555] PLATE II. FIG. 1. It has been ascertained that the spurious
elytra of these insects are serviceable in their flight. As M.
Latreille now allows this, he ought to have restored its original
name, which he had altered, to this order.
[556] PLATE X. FIG. 2.
[557] _Hist. Ins._ 63.
[558] _Nat. Hist._ ii. 82.
[559] PLATE II. FIG. 4.
[560] PLATE X. FIG. 3. II. FIG. 5.
[561] PLATE XV. FIG. 2. I have separated this tribe from the rest
under the name of _Petalopus_, K. Ms.
[562] PLATE III. FIG. 4.
[563] Lesser, _L._ i. 109, note *. De Geer, ii. 460-- _t._ ix. _f._ 9.
[564] PLATE XXII. FIG. 16--.
[565] PLATE X. FIG. 6.
[566] De Geer, i. 173. _t._ x. _f._ 4. _Linn. Trans._ i. 135--.
[567] _Linn. Trans._ vii. 40.
[568] Haworth _Lepidopt. Brit._ i. 19.
[569] Leeuw. _Epist._ 6. Mart. 1717.
[570] Jurine _Hymenopt._ t. 2-5.
[571] Kirby _Mon. Ap. Angl._ i. 96. 108. _t._ xiii. _f._ 19.
[572] Ibid. 96. 107. _t._ v. _f._ 8. _dd._
[573] Huber, i. 38.
[574] _Phys. Theol._ 13th Ed. 366, note (_i._)
[575] Wiedemann's _Archiv._ ii. 210.
[576] To those that frequent meadows and pastures (_Tipula oleracea_,
L. &c.) they are also useful as I have before observed, as stilts, to
enable them to walk over the grass. Reaum. v. _Pref._ i. _t._ iii.
_f._ 10.
[577] 4to. iii. 36.
[578] PLATE XIV. FIG. 6.
[579] Mr. Briggs observes that this insect appears to move all its
legs at once, with wonderful rapidity, by which motion it produces a
radiating vibration on the surface of the water.
[580] De Geer, iii. 314.
[581] VOL. I. 470--.
[582] Curtis _Brit. Ent._ _t._ ii.
[583] PLATE XV. FIG. 5.
[584] PLATE II. FIG. 2.
[585] PLATE XV. FIG. 6. _s´´._, _v´´´._
[586] Ibid. _t´´._
[587] White, _Nat. Hist._ ii. 80. 72. 76.
[588] _Linn. Trans._ iv. 200--.
[589] v. 20--.
[590] vi. 104.
[591] Rai. _Hist. Ins._ 133. l.
[592] Lesser, _L._ i. 248, note 22.
[593] VOL. I. 282--.
[594] Reaum. vi. 484. _t._ xlv. _f._ 7.
[595] The persons observing the appearance here related were the
authors of this work.
[596] _Lach. Lapp._ i. 194.
[597] Compare Oliv. _Entomol._ iii. _Gyrinus_ 4.
[598] De Geer, ii. 638--.
[599] See above, p. 7.
LETTER XXIV.
_ON THE NOISES PRODUCED BY
INSECTS._
That insects, though they fill the air with a variety of sounds, have
no _voice_, may seem to you a paradox, and you may be tempted to
exclaim with the Roman naturalist, What, amidst this incessant diurnal
hum of bees; this evening boom of beetles; this nocturnal buz of gnats;
this merry chirp of crickets and grasshoppers; this deafening drum
of Cicadæ, have insects no voice! If by voice we understand sounds
produced by the air expelled from the lungs, which, passing through
the larynx, is modified by the tongue, and emitted from the mouth,--it
is even so. For no insect, like the larger animals, uses its mouth for
utterance of any kind: in this respect they are all perfectly mute; and
though incessantly noisy, are everlastingly silent. Of this fact the
Stagyrite was not ignorant, since, denying them a voice, he attributes
the sounds emitted by insects to another cause. But if we feel disposed
to give a larger extent to this word; if we are of opinion that all
sounds, however produced, by means of which animals determine those of
their own species to certain actions, merit the name of voice; then I
will grant that insects have a voice. But, decide this question as we
will, we all know that by some means or other, at certain seasons and
on various occasions, these little creatures make a great din in the
world. I must therefore now bespeak your attention to this department
of their history.
In discussing this subject, I shall consider the noises insects
emit--during their motions--when they are feeding, or otherwise
employed--when they are calling or commanding--or when they are under
the influence of the passions; of fear, of anger, of sorrow, joy, or
love.
The only kind of _locomotion_ during which these animals produce
sounds, is flying: for though the hill-ants (_Formica rufa_), as I
formerly observed[600], make a rustling noise with their feet when
walking over dry leaves, I know of no other insect the tread of which
is accompanied by sound--except indeed the flea, whose steps, a
lady assures me, she always hears when it paces over her night-cap,
and that it clicks as if it was walking in pattens! That the flight
of numbers of insects is attended by a humming or booming is known
to almost every one; but that the great majority move through the
air in silence, has not perhaps been so often observed. Generally
speaking, those that fly with the most force and rapidity, and with
wings seemingly motionless, make the most noise; while those that fly
gently and leisurely, and visibly fan the air with their wings, yield
little or no sound.
Amongst the beetle tribes (_Coleoptera_), none is more noticed, or
more celebrated for "wheeling its droning flight," than the common
dung-chafer (_Geotrupes stercorarius_) and its affinities. Linné
affirms--but the prognostic sometimes fails--that when these insects
fly in numbers, it indicates a subsequent fine day[601]. The truth
is, they only fly in fine weather. Mr. White has remarked, that in
the dusk of the evening beetles begin to buz, and that partridges
begin to call exactly at the same time[602]. The common cock chafer,
and that which appears at the summer solstice (_Melolontha vulgaris_
and _Amphimalla solstitialis_), when they hover over the summits of
trees in numbers, produce a hum somewhat resembling that of bees
swarming. Perhaps some insect of this kind may occasion the humming
in the air mentioned by Mr. White, and which you and I have often
heard in other places. "There is," says he, "a natural occurrence to
be met with in the highest part of our down on the hot summer days,
which always amuses me much, without giving me any satisfaction with
respect to the cause of it;--and that is a loud audible humming of
bees in the air, though not one insect is to be seen.--Any person
would suppose that a large swarm of bees was in motion, and playing
about over his head[603]."
"Resounds the living surface of the ground--
Nor undelightful is the ceaseless hum
To him who muses through the woods at noon,
Or drowsy shepherd as he lies reclined."
The hotter the weather, the higher insects will soar; and it is
not improbable that the sound produced by numbers may be heard,
when those that produce it are out of sight.--The burying-beetle
(_Necrophorus Vespillo_), whose singular history[604] so much amused
you, as well as _Cicindela sylvatica_ of the same order, flies
likewise, as I have more than once witnessed, with a considerable hum.
Whether the innumerable locust armies, to which I have so often called
your attention, make any noise in their flight, I have not been able
to ascertain; the mere impulse of the wings of myriads and myriads
of these creatures upon the air, must, one would think, produce some
sound. In the symbolical locusts mentioned in the Apocalypse[605], this
is compared to the sound of chariots rushing to battle: an illustration
which the inspired author of that book would scarcely have had recourse
to, if the real locusts winged their way in silence.
Amongst the _Hemiptera_, I know only a single species that is of noisy
flight; though doubtless, were the attention of entomologists directed
to that object, others would be found exhibiting the same peculiarity.
The insect I allude to (_Coreus marginatus_) is one of the numerous
tribe of bugs; when flying, especially when hovering together in a
sunny sheltered spot, they emit a hum as loud as that of the hive-bee.
From the magnitude and strength of their wings, it might be supposed
that many _lepidopterous_ insects would not be silent in their
flight;--and indeed many of the hawk-moths (_Sphinx_, F.), and some
of the larger moths (_Bombyx_, F.), are not so; _Cossus ligniperda_,
for instance, is said to emulate the booming of beetles by means
of its large stiff wings; whence in Germany it is called the
humming-bird (_Brumm-Vogel_).--But the great body of these numerous
tribes, even those that fan the air with "sail-broad vans," produce
little or no sound by their motion. I must therefore leave them,
as well as the _Trichoptera_ and _Neuroptera_, which are equally
barren of insects of sounding wing--and proceed to an order, the
_Hymenoptera_, in which the insects that compose it are, many of
them, of more fame for this property.
The indefatigable hive-bee, as she flies from flower to flower,
amuses the observer with her hum, which, though monotonous, pleases
by exciting the idea of happy industry, that wiles the toils of
labour with a song. When she alights upon a flower, and is engaged in
collecting its sweets, her hum ceases; but it is resumed again the
moment that she leaves it.--The wasp and hornet also are strenuous
hummers; and when they enter our apartments, their hum often brings
terror with it. But the most sonorous fliers of this order are the
larger humble-bees, whose _bombination_, _booming_, or _bombing_, may
be heard from a considerable distance, gradually increasing as the
animal approaches you, and when, in its wheeling flight, it rudely
passes close to your ear, almost stunning you by its sharp, shrill,
and deafening sound. Many genera, however, of this order fly silently.
But the noisiest wings belong to insects of the _dipterous_ order,
a majority of which, probably, give notice of their approach by
the sound of their trumpets. Most of those, however, that have a
slender body,--the gnat genus (_Culex_) excepted,--explore the air
in silence. Of this description are the _Tipulariæ_, the _Asilidæ_,
the genus _Empis_, and their affinities. The rest are more or less
insects of a humming flight; and with respect to many of them, their
hum is a sound of terror and dismay to those who hear it. To man, the
trumpet of the gnat or mosquito; and to beasts, that of the gad-fly;
of various kinds of horse-flies; and of the Ethiopian zimb, as I have
before related at large[606], is the signal of intolerable annoyance.
Homer, in his _Batrachomyomachia_, long ago celebrated the first of
these as a trumpeter--
"For their sonorous trumpets far renown'd,
Of battle the dire charge mosquitos sound."
Mr. Pope, in his translation, with his usual inaccuracy, thinking no
doubt to improve upon his author, has turned the old bard's gnats
into hornets. In Guiana these animals are distinguished by a name
still more tremendous, being called the devil's trumpeters[607]. I
have observed that early in the spring, before their thirst for blood
seizes them, gnats when flying emit no sound. At this moment (Feb.
18) two females are flying about my windows in perfect silence.
After this short account of insects that give notice when they are
upon the wing by the sounds that precede them, I must inquire by
what means these sounds are produced. Ordinarily, except perhaps in
the case of the gnat, they seem perfectly independent of the will of
the animal; and in almost every instance, the sole instruments that
cause the noise of flying insects are their wings, or some parts
near to them, which, by their friction against the trunk, occasion
a vibration--as the fingers upon the strings of a guitar--yielding
a sound more or less acute in proportion to the rapidity of their
flight--the action of the air perhaps upon these organs giving it
some modifications. Whether, in the beetles that fly with noise,
the elytra contribute more or less to produce it, seems not to have
been clearly ascertained: yet, since they fly with force as well as
velocity, the action of the air may cause some motion in them, enough
to occasion friction. With respect to _Diptera_, Latreille contends
that the noise of flies on the wing cannot be the result of friction,
because their wings are then expanded; but though to us flies seem
to sail through the air without moving these organs, yet they are
doubtless all the while in motion, though too rapid for the eye to
perceive it. When the aphidivorous flies are hovering, the vertical
play of their wings, though very rapid, is easily seen; but when they
fly off it is no longer visible. Repeated experiments have been tried
to ascertain the cause of sound in this tribe, but it should seem
with different results. De Geer, whose observations were made upon
one of the flies just mentioned, appears to have proved that, in the
insect he examined, the sounds were produced by the friction of the
root or base of the wings against the sides of the cavity in which
they are inserted. To be convinced of this, he affirms, the observer
has nothing to do but to hold each wing with the finger and thumb,
and stretching them out, taking care not to hurt the animal, in
opposite directions, thus to prevent their motion,--and immediately
all sound will cease. For further satisfaction he made the following
experiment. He first cut off the wings of one of these flies very
near the base; but finding that it still continued to buz as before,
he thought that the winglets and poisers, which he remarked were in
a constant vibration, might occasion the sound. Upon this, cutting
both off, he examined the mutilated fly with a microscope, and found
that the remaining fragments of the wings were in constant motion all
the time that the buzzing continued; but that upon pulling them up
by the roots all sound ceased[608]. Shelver's experiments, noticed
in my last letter, go to prove, with respect to the insects that he
examined, that the winglets are more particularly concerned with the
buzzing. Upon cutting off the wings of a fly--but he does not state
that he pulled them up by the roots--he found the sound continued.
He next cut off the poisers--the buzzing went on. This experiment
was repeated eighteen times with the same result. Lastly, when he
took off the winglets, either wholly or partially, the buzzing
ceased. This, however, if correct, can only be a cause of this noise
in the insects that have winglets. Numbers have them not. He next,
therefore, cut off the poisers of a crane-fly (_Tipula crocata_),
and found that it buzzed when it moved the wing. He cut off half the
latter, yet still the sound continued; but when he had cut off the
whole of these organs the sound entirely ceased[609].
Aristophanes in his _Clouds_, deriding Socrates, introduces Chærephon
as asking that philosopher whether gnats made their buz with their
mouth or their tail[610]. Upon which Mouffet very gravely observes,
that the sound of one of these insects approaching is much more acute
than that of one retiring; from whence he very sapiently concludes,
that not the tail but the mouth must be their organ of sound[611].
But after all, the friction of the base of the wings against the
thorax seems to be the sole cause of the alarming buz of the gnat as
well as that of other _Diptera_. The warmer the weather, the greater
is their thirst for blood, the more forcible their flight, the motion
of their wings more rapid, and the sound produced by that motion more
intense. In the night--but perhaps this may arise from the universal
stillness that then reigns--their hum appears louder than in the day:
whence its tones may seem to be modified by the will of the animal.
Sounds also are sometimes emitted by insects when they are _feeding_
or otherwise _employed_. The action of the jaws of a large number of
cockchafers produces a noise resembling the sawing of timber; that
of the locusts has been compared to the crackling of a flame of fire
driven by the wind; indeed the collision at the same instant of myriads
of millions of their powerful jaws must be attended by a considerable
sound. The timber-borers also--the _Buprestes_; the stag-horn beetles;
and particularly the capricorn-beetles--the mandibles of whose larvæ
resemble a pair of mill-stones[612]--most probably do not feed in
silence. A little wood-louse (_Atropos pulsatoria_)--which on that
account has been confounded with the death-watch--is said also, when
so engaged, to emit a ticking noise.--Certain two-winged flies seen
in spring, distinguished by a very long proboscis (_Bombylius_), hum
all the time that they suck the honey from the flowers; as do also
many hawk-moths, particularly that called from this circumstance the
humming-bird (_Macroglossa Stellatarum_), which, while it hovers
over them, unfolding its long tongue, pilfers their sweets without
interrupting its song.--The giant cock-roach (_Blatta gigantea_), which
abounds in old timber houses in the warmer parts of the world, makes a
noise when the family are asleep like a pretty smart rapping with the
knuckles--three or four sometimes appearing to answer each other.--On
this account in the West Indies it is called the _Drummer_; and they
sometimes beat such a reveille, that only good sleepers can rest for
them[613]. As the animals of this genus generally come forth in the
night for the purpose of feeding, this noise is probably connected with
that subject.
Insects also, at least many of the social ones, emit peculiar noises
while engaged in their various _employments_. If an ear be applied to
a wasps or humble-bees nest, or a bee-hive, a hum more or less intense
may always be perceived. Were I disposed to play upon your credulity,
I might tell you, with Gœdart, that in every humble-bees nest there
is a trumpeter, who early in the morning, ascending to its summit,
vibrates his wings, and sounding his trumpet for the space of a quarter
of an hour, rouses the inhabitants to work! But since Reaumur could
never witness this, I shall not insist upon your believing it, though
the relater declares that he had heard it with his ears, and seen
it with his eyes, and had called many to witness the vibrating and
strepent wings of this trumpeter humble-bee[614].--The blue sand-wasp
(_Ammophila? cyanea_), which at all other times is silent, when engaged
in building its cells emits a singular but pleasing sound, which may be
heard at ten or twelve yards distance[615].
Some insects also are remarkable for a peculiar mode of _calling_,
_commanding_, or giving an _alarm_. I have before mentioned the noise
made by the neuters or soldiers amongst the white ants, by which
they keep the labourers, who answer it by a hiss, upon the alert
and to their work[616]. This noise, which is produced by striking
any substance with their mandibles, Smeathman describes as a small
vibrating sound, rather shriller and quicker than the ticking of
a watch. It could be distinguished, he says, at the distance of
three or four feet, and continued for a minute at a time with very
short intervals. When any one walks in a solitary grove, where the
covered ways of these insects abound, they give the alarm by a loud
hissing, which is heard at every step[617].--"When house-crickets
are out," says Mr. White, "and running about in a room in the night,
if surprised by a candle they give two or three shrill notes, as it
were for a signal to their followers, that they may escape to their
crannies and lurking-holes to avoid danger[618]."
Under this head I shall consider a noise before alluded to[619],
which has been a cause of alarm and terror to the superstitious in
all ages. You will perceive that I am speaking of the death-watch--so
called, because it emits a sound resembling the ticking of a watch,
supposed to predict the death of some one of the family in the house
in which it is heard. Thus sings the muse of the witty Dean of St.
Patrick on this subject:
"..................A wood-worm
That lies in old wood, like a hare in her form:
With teeth or with claws it will bite or will scratch,
And chambermaids christen this worm a death-watch;
Because like a watch it always cries click;
Then woe be to those in the house who are sick!
For, sure as a gun, they will give up the ghost,
If the maggot cries click, when it scratches the post;
But a kettle of scalding hot water injected,
Infallibly cures the timber affected:
The omen is broken, the danger is over,
The maggot will die, and the sick will recover."
To add to the effect of this noise, it is said to be made only when
there is a profound silence in an apartment, and every one is still.