By Grant Allen.
Human life and especially human warfare are rich in deceptions, wiles,
and stratagems. We dig pitfalls for wild beasts, carefully concealed by
grass and branches; we take in the unsuspecting fish with artificial
flies, or catch them with worms which conceal a hook treacherously
barbed for their surer destruction. The savage paints his face and
sticks feathers in his hair so that he may look more terrifying to his
expected enemy; civilized men mask their batteries, and sometimes even
paint muzzles of imaginary guns in the spaces between the gaping mouths
of the real ones. _Chevaux de frise_ block the way to points liable to
attack; real troops lie in ambush and dart out unexpectedly in the rear
of the assailants. Trade in like manner is full of shams--a fact which I
need hardly impress by means of special examples. But Nature we are
usually accustomed to consider as innocent and truthful. Alas, too
trustfully: for Nature too is a gay deceiver. There is hardly a device
invented by man which she has not anticipated: hardly a trick or ruse in
his stock of wiles which she did not find out for herself long before he
showed her.
I propose in this paper to examine a few cases of such natural
deceptions--not indeed the most striking or typical, but such as occur
among fairly well-known English plants and animals. And I shall begin
with our familiar and unsavoury old friend, the Devil's Coach-horse.
[Illustration: 1.--A BATTLE ROYAL: SCORPION V. SPIDER: THE SCORPION
STRIKING.]
In order fully to understand his mode of procedure, however, I must
first call your attention to another animal which really _is_ what the
Devil's Coach-horse mendaciously pretends to be: and that is the common
scorpion. His mode of fighting is well known to most of us. In
illustration No. 1 Mr. Enock has given us a delineation of a frantic
death-struggle between such a scorpion and a large and powerful southern
spider. The venomous creature with the stinging tail is on the left; the
spider is on the right. As far as mere size goes, the antagonists are
fairly well matched: but the scorpion is the best armed, both with
offensive and defensive armour. His lobster-like or crab-like claws
enable him to hold his enemy's limbs in his grip as in a vice: then, at
the critical moment, he bends over his tail, in the extremity of which
his sting is situated, and plunges it with force through the
comparatively slight skin of the spider's body or thorax, injecting at
the same moment a pungent drop of his deadly poison. This characteristic
action of the scorpion in curving its tail over its body and raising its
sting in a menacing attitude is well known to birds and other enemies
of the species: often the mere threat of a thrust is a sufficient
deterrent: the dangerous beast just elevates its poisonous appendage or
assumes an angry mien, and the inquisitive intruder is frightened away
immediately. It is the same with ourselves. The bare sight of that
uplifted sting suffices to repel us. Even a child who saw a scorpion
once arch its back and prepare to strike with its reversed tail would
instinctively understand that there was danger ahead, and would withdraw
its hand before the venomous creature had time to pounce upon it.
Owing to these unamiable personal traits of the scorpion race, it is not
popular among other animals. But to be feared is to be respected; and
scorpions for the most part are left severely alone, under the stones
where they love to lurk, by the various denizens of the districts they
inhabit. Now, it is a fact in nature as in human life that to be
successful is to have many imitators. Thus a number of harmless flies
dress up like wasps in black and yellow bands, and so escape the too
pressing attentions of insect-eating birds and other enemies. They have
no stings, to be sure, but they look so like the wasps, and flaunt about
so fearlessly in their borrowed uniform, that they are universally taken
for the insects they mimic; even the cautious entomologist himself
stares at them twice and makes quite sure of his specimen before he
ventures to lay hands on any such doubtful masquerader. I hope in a
future article to give some further account (with illustrations) of
these facts of _mimicry_, as it is called: for the present we will stick
close to our text, the Devil's Coach-horse. For this familiar English
beetle is an imitator of the scorpion, and obtains immunity from the
attack of enemies to a great extent by pretending to powers which are
not his in reality.
[Illustration: 2.--THE DEVIL'S COACH-HORSE IN HIS HOURS OF EASE.]
In No. 2 we have a portrait of the Coach-horse in his hours of ease,
seen from above, engaged in doing nothing in particular. He does not
_look_ like a flying insect, but he is. He has a long pair of wings
tucked away in folds under his horny wing-cases, and he can use them
with great effect, for he is one of our swiftest and strongest
fliers--the long-distance champion, I almost fancy, among the beetles of
England, unless indeed the tiger-beetle be pitted against him. But when
crawling on the ground, and attacked or menaced, he does not take to
flight or show the white feather: being a pugnacious and spirited little
beast, he bridles up at once, and endeavours incontinently to terrify
his assailant. In No. 2 you see him from above when he is merely engaged
in crawling along the ground, looking as mild as milk, and as gentle as
any sucking dove: you would hardly suppose he could show fight or raise
his hand--I mean his antennæ--to injure anyone. But in No. 3 he is
represented in his favourite act of attacking a caterpillar: for he is
really a very voracious and courageous carnivore. In the autumn, when
Devil's Coach-horses are usually most abundant, you can easily catch
them by putting a piece of meat or a dead frog under an empty
flower-pot, and then tilting the edge up with a stone, so that the
beetles can crawl in and get at the food thus temptingly laid out for
them.
[Illustration: 3.--THE DEVIL'S COACH-HORSE SAMPLING A CATERPILLAR.]
If you disturb the Coach-horse, however, while he is engaged in eating
his quiet meal, or even when he is walking at leisure along a country
road, he puts himself at once into his "terrifying" attitude, and
imitates the scorpion. No. 4 exhibits him in this military character,
cocking up his tail and pretending he can sting--which is only his brag:
he just does it to frighten you. But the attitude is so exactly like
that of the scorpion, that it almost always produces an immediate
effect: hardly anybody likes to molest a Devil's Coach-horse. If you put
down your hand to touch him, and he rears in response, ten to one you
will withdraw it in alarm at sight of him. In England these beetles
often enough find their way into larders or cellars, seeking whom or
what they may devour; and when the servants light upon them, they almost
invariably decline to touch them: there is a general opinion about that
the ugly and threatening black beasts are uncanny and poisonous, or else
why should they turn up their tails at you in such an insulting fashion?
[Illustration: 4.--THE DEVIL'S COACH-HORSE PRETENDS TO BE A SCORPION.]
"But," you may object, "there are no scorpions in England: how then can
the Devil's Coach-horse be benefited by imitating an animal which he has
never seen, and of whose very existence he has not been able to read in
pretty picture books?" Your objection has some force--though not so much
as you imagine. It is quite true that there are no scorpions in England;
but then, there are Devil's Coach-horses in many other countries, and
the habit of tail-cocking need not necessarily have been acquired in
these islands of Britain. That is not all, however: it suffices the
beetle if the tactics it adopts happen to frighten and repel its
enemies, no matter why. Now, in the first place, many of our migratory
birds go in winter to Southern Europe and Africa--especially the
insect-eaters, which can find no food in frozen weather. The hard-billed
seed-eaters and fruit-eaters remain with us, but the soft-billed kinds
retire to warmer climates, where food is plentiful. Of course, however,
it is just these insect-eating birds that the Devil's Coach-horse has
most to fear from. The birds must be quite familiar with the habits and
manners of scorpions in their southern homes; and they are not likely to
inquire closely whether the dangerous beast they know on the
Mediterranean has, or has not been scheduled in Britain. We all of us
dislike and distrust any insect that resembles a bee or wasp, and that
buzzes or hums in a hostile manner: we give all such creatures a wide
berth, wherever found, on the bare off-chance that they may turn out to
be venomous--be hornets or so forth. Just in the same way, a bird, when
it sees an unknown black beastie cock up its tail and assume a
threatening attitude, is not likely to inquire too curiously whether or
not it is really a scorpion: the bare suspicion of a sting is quite
enough to warn it off from interfering with any doubtful customer.
Moreover, in the second place, even those birds or men who have never
seen a scorpion at all are yet sure to be alarmed when an insect sticks
up its forked tail menacingly, and shows fight, instead of skulking or
flying away. As a general rule, if any animal makes signs of resistance,
we take it for granted he has adequate arms or weapons to resist with:
and so this mere dumb-show of being a sort of scorpion proves quite
sufficient to protect the Devil's Coach-horse from the majority of his
enemies.
I ought to add that while our beetle thus frightens larger enemies, he
is actively and offensively objectionable to small ones. The main use of
his tail, indeed, is for folding away his wings, much as the earwig
folds hers by aid of her pincers. But the Devil's Coach-horse makes it
serve a double purpose. For he has a couple of yellow scent-glands in
his tail, which secrete an unpleasant and acrid aromatic substance.
These scent-glands are protruded in No. 4: you can just see them at the
tip of the tail; and if the annoyance to which the beetle is subjected
seems to call for their intervention, a drop of the volatile body they
distil is set free, and is at once discharged in the face of the enemy.
Such a manoeuvre is in essence like that of the skunk: it is defence by
means of a nasty odour, and it occurs not only in the Coach-horse's
case, but also among a number of beetles and other insects.
The odd little creatures known as Bombardier Beetles are still quainter
in their habits: they carry the last-mentioned mode of defence to an
even greater pitch of perfection. For, like miniature artillery-men,
they actually fire off a regular volley of explosive gas in the faces of
their pursuers. The gas is secreted as a liquid; but it is very
volatile, and it vaporizes at once on contact with the air, so as to
form a small, white cloud of pungent smoke, resembling in its effects
nitric acid. Our native English species of Bombardier roams about in
large flocks or regiments: and when one member of a clan is disturbed,
all the other beetles of the company let off their artillery at once, so
that the scattered volley has something the appearance of platoon
firing. The chief enemy of the Bombardiers is a much larger and very
handsome carnivorous beetle known as Calosoma. When this insect tiger
hunts down a single Bombardier, and has almost caught him, the fugitive
waits till his pursuer is quite close, and then salutes him with a
discharge of fire-arms: the pungent gas gets into the Calosoma's eyes
and mouth and distracts him for a moment; and the Bombardier escapes in
the midst of the confusion thus caused, under cover of the cloud he
himself has exploded. That is the most highly evolved mode of defence of
which I know among the British insects.
There are few creatures, again, which one would so little suspect of any
attempt to bully and bluff others as the soft-bodied caterpillars. They
are as a rule so plump and squashy and defenceless: a mere peck from a
bird's beak is enough to kill them, for when once their tight, thin skin
is broken, were it but with a pin-prick, all the flabby contents burst
out at once in the messiest fashion. Yet even caterpillars, strange to
say, have their tricks of terrifying. They pretend to be dangerous
characters. I will set out with some of the simplest and least developed
cases, and then pass on to a more complex and wily class of deceivers.
To begin with, I must premise that two sets of caterpillars have two
different ways of evading the unpleasant notice of birds and other
insect-eaters. One way is that adopted by the common "woolly-bear," a
great hairy caterpillar, frequent in gardens, and covered from head to
tail with long needles or bristles. These prickly points make the
creature into a sort of insect hedgehog; birds refuse to touch him,
because the serried spikes, which to us are mere hairs, seem to them
perfect spines or thorns, sticking into their tongues and throats, or
clogging their gizzards. Protected caterpillars like the woolly-bears
live quite openly, exposed on the leaves and branches of their
food-plant; they are not afraid of being seen: nay, they rather court
observation than shun it, because they know nobody will attack them. The
porcupine has no need to run away like the rabbit. Similar tactics are
also adopted by many nasty-tasting caterpillars, in whose bodies natural
selection has developed bitter or unpleasant juices. These caterpillars
are rejected by birds and lizards--the great enemies of the race--and
therefore they find it worth while to clothe themselves in gaudy and
conspicuous red or yellow bands, so as to advertise all comers of their
inedible qualities. Whenever you see such brilliantly-attired grubs
(like those of the Magpie Moth, so common on gooseberry-bushes--a
striking creature tricked out in belts of black and orange), you may be
sure of two things: first, they live openly and undisguisedly on the
leaves of their food-plant, without any attempt at mean concealment; and
second, they are nasty to the taste, and therefore rejected as food by
insect-eating animals. Now and then a young and inexperienced bird may
eat one, to be sure; but it never tries twice, and the solitary martyr
is sacrificed for the good of the race. Their bright colours and gaudy
bands are just advertisements, as it were, of their inedible qualities.
For, of course, nasty taste would do a caterpillar no good if the bird
had always to sample it before rejecting it; the broken skin alone would
be enough to kill it. Hence almost all uneatable caterpillars have
acquired bright colours by natural selection--that is to say, by the
less bright being continuously devoured or killed; and birds on their
side have learned to know (after one trial, or, perhaps, even before it
by inherited instinct) that red or yellow bands and belts in
caterpillars are the outward and visible sign of uneatableness.
The second group or set of caterpillars is edible and tasty: it,
therefore, governs itself accordingly, and has recourse to the exactly
opposite tactics. Caterpillars of this class are smooth and naked: they
never have the brilliant "warning colours" of the nasty-tasted kinds:
and they show a marked absence of the beautiful metallic sheen, the
strange melting iridescent hues and spots which add beauty to the charms
of so many among the uneatable species. Such fat and smooth-skinned
edible caterpillars are, of course, very tempting juicy morsels to birds
and other insect-eating animals. Their motions, like those of all grubs,
are slow; and if they lived exposed on their food-plants, after the
fashion of the protected hairy and bitter kinds, they would all he eaten
up before they had time to turn into moths or butterflies. Here,
therefore, natural selection has produced the contrary result from that
which it produces among protected kinds. Caterpillars of this edible
type which showed themselves too openly and imprudently have got picked
off by birds, like sentries and pickets who make themselves too
conspicuous to the enemy's sharpshooters. Only the most prudent, modest,
and retiring grubs have survived to become moths or butterflies, and so
be the parents of future generations, to whom they hand on their own
peculiarities. In this way the edible caterpillars have acquired at last
a fixed hereditary instinct of lurking under leaves, or in dark spots,
and never showing themselves openly. The larvæ of the butterfly group as
a whole thus fall into two great classes (as far as regards habits
alone, I mean): the _protected_, which are either hairy or nasty, and
which flaunt themselves openly; and the _unprotected_, which lurk and
skulk, endeavouring to escape notice as sedulously as their rivals the
protected endeavour to attract it.
Nor is that all. It would clearly be useless for a bright red or yellow
caterpillar to hide under a green leaf, and then suppose by that simple
device he was going to escape observation. Birds are always looking out
for insects under leaves. The consequence is that skulking or lurking
caterpillars are soon found out by sharp-eyed and hungry enemies, unless
they closely resemble the foliage or stems upon which they lie. From
generation to generation, accordingly, the less imitative insects get
eaten, and the more imitative spared: so that nowadays, most unarmed
caterpillars are green like the leaves or grey like the stems, and are
even provided with markings of light and shade upon their skins which
mimic the distribution of light and shade among the ribs and veins of
the surrounding foliage. Such deceptive leaf-like caterpillars are
always very difficult to find: so that careless observers as a rule know
only those of the other type, the great hairy "woolly-bears" and the
brilliant red and yellow-banded bitter kinds; they never observe the
unobtrusive green and brown sorts, which harmonize so admirably with
their native tree in colour and markings.
[Illustration: 5.--CATERPILLAR OF THE BROAD-BORDERED BEE-HAWK TRYING TO
LOOK ALARMING.]
Many greenish caterpillars, however, when discovered and disturbed, fall
back on their second line of defence: they endeavour to frighten their
enemies by devices closely similar to those of the Devil's Coach-horse.
The caterpillar of the Broad-bordered Bee-hawk, for example, forms a
good instance of a very simple stage in the development of such
brazen-faced "terrifying" tactics. This warlike grub is shown in No. 5,
trying on its simple little attempt to make itself alarming. Though by
no means an uncanny-looking or appalling insect, it will rear itself up
on its haunches (so to speak) when attacked, raising the fore part of
its body erect with a sudden jerk, and holding its head high, as if it
meant to bite or sting, so as to give itself as formidable an aspect as
possible. The mild ruse succeeds, too; for birds will eye the harmless
creature askance when it attempts this evolution, putting their heads on
one side, and ruffling their crests in evident terror. The attitude is
all a simple piece of bluff, to be sure, but _it pays_; indeed, bluff
in warfare is often more than half the battle. If you put on a bold face
in a row, and seem able to take care of yourself, people are apt to
think you have a knife up your sleeve, and therefore to refrain from
unnecessarily annoying you.
The cunning caterpillar which finally develops into the Privet Hawk-moth
has a slightly more evolved mode of purely theatrical frightening. You
see him in No. 6, a full-fed specimen, just ready to turn at once into a
chrysalis. This grub feeds usually on the vivid leaves of the privet; he
is therefore protectively coloured a bright green, like that of the
foliage about him. "But why those great purple stripes on his sides?"
you will ask. "Surely they must make him an easy mark for birds?" Not at
all: please notice that they run obliquely. There is method in that
obliquity. When the caterpillar is smaller, he lurks unseen on the
under-side of the leaves, and this pattern of oblique purplish lines
exactly imitates the general effect of the shadows cast by the ribs--so
much so, that if you look for him on a privet-tree in spring, I doubt
whether you will find him till I point him out to you. Even when he
waxes fat and full fed, the purple stripes still aid him more or less by
breaking up the large green surface into smaller areas, as Professor
Poulton has well noticed. He harmonizes better so with the broken masses
of the leaves about him. Then again, when the time arrives for him to
turn into a chrysalis, he descends to the ground, which, under a
thickly-leaved privet bush, is most often brown. So, just as he is
coming of age and reaching the proper moment for migration, his back all
at once begins to turn brown, in order that he may be less observed as
he walks about on the stem; while by the time he is quite ready to take
to the earth he has grown brown all over, thus matching the soil in
which he has next to bury himself. You could hardly have a better
example of the sort of colour-change which often accompanies altered
habits of living.
[Illustration: 6.--FULL-GROWN CATERPILLAR OF THE PRIVET HAWK-MOTH,
SIMILARLY OCCUPIED.]
In the illustration, however, you see this really harmless and
undefended grub in the act of trying to pretend he is poisonous. He is
now mature, and the stripes on his sides stand out conspicuously as he
walks on the stem. A sparrow threatens him. He retorts by showing
fight--fallaciously and deceptively, for he has nothing to fight with.
He lifts his head with an aggressive air, and throws himself about from
side to side, as if he knew he could bite, and meant to do it. He also
lashes his tail in pretended anger--"I would have you to know, Sir Bird,
I am not to be trifled with!" The empty demonstration usually succeeds:
the sparrow gets alarmed and believes he means it. This policy is, in
essence, that commonly known as "spirited": it consists in trying to
frighten your enemy instead of fighting him.
The oddly-marked caterpillar of the Puss Moth carries the same plan of
campaign to a much more artistic pitch. This very quaint insect is
common on willows and poplars in England, and is on the whole
protectively coloured. Black at first, it looks like a mere speck or
spot on the leaf; as it grows, it becomes gradually greener, relieved
with broad purple patches on the back, which produce the effect of lines
and shadows. When quite full-grown, as seen in No. 7, the adult
caterpillar generally rests at ease on the twigs of the willow-tree. Our
illustration shows it in this final stage of its larval life, just
taking alarm and humping its back at the approach of some bird or other
enemy. If the alarm continues, it goes through a most curious series of
evolutions, admirably shown by Mr. Enock in No. 8. Here, the little
beast is altogether on the defensive: it withdraws its head into the
first ring of the body, and inflates the margin, which is bright red in
colour. Two black spots, which are not really eyes, but which look
absurdly eye-like, now give it a grotesque and terrifying appearance. In
fact, the inflated ring resembles a hideous grinning mask, and gives the
impression of a face with eyes, nose, and mouth, like that of some
uncanny creeping creature. But the apparent face is not a face at all:
it is artfully made up of lines and spots on the skin of the body. At
the same time that the caterpillar thus assumes its mask, it stands on
its eight hind legs as erect as it can, and whips out two pink bristles
or tentacles from the forked prongs at the end of its tail--you can see
them in the picture. It then bends forward the tail, and brandishes or
waves about these pink bristles over its false head, so as to present
altogether a most gruesome aspect. Indeed, even Mr. Enock's vigorous
sketch of the little brute in its tragic moments does not quite convey
the full effect of its acting in the absence of colour: for the bright
red margin and the swishing pink switches add not a little to the
telling smirk and black goggle-eyes of the mask-like face thus produced
_in terrorem_.
[Illustration: 7.--CATERPILLAR OF THE PUSS MOTH PREPARING FOR ACTION.]
That is not all, either. The Puss Moth caterpillar has a rapid trick of
facing about abruptly in the direction of the enemy as if it meant to
bite: and this trick is always most disconcerting. If ever so lightly
touched, it instantly assumes the terrifying attitude, and presents its
pretended face to the astonished aggressor. From a harmless caterpillar
it becomes all at once a raging bulldog. Touch it on the other side, and
it faces round like lightning in the opposite direction. Professor
Poulton tried the effect of its grimace on a marmoset, and found the
marmoset was afraid to touch the mysterious creature. We are not
marmosets, but I notice that most human beings recoil instinctively from
a Puss Moth caterpillar when it assumes its mask. Even if you _know_ it
is harmless, there is something very alarming in its rapid twists and
turns, and in the persistent way in which it grins and spits at you.
[Illustration: 8.--THE SAME CATERPILLAR TERRIFYING AN ENEMY.]
Really spits, too; for the insect has a gland in its head which ejects,
at need, an irritating fluid. If this fluid gets into your eyes, they
smart most unpleasantly. It contains formic acid, and is strong enough
to be exceedingly stinging and painful. The discharge repels lizards,
and probably also birds, who are among the chief enemies of this as of
other caterpillars.
The deadliest foe of the Puss Moth larva, however, is the ichneumon-fly,
a parasitic creature, which lays its eggs in living caterpillars, and
lets its grubs hatch out inside them, so as to devour the host from
within in the most ruthless fashion. There are many kinds of
ichneumon-fly, some of them very minute: the one which attacks the Puss
Moth in its larval stage is a comparatively big one. The fly lays its
eggs behind the caterpillar's head, where the victim is powerless to
dislodge them. In all probability the defensive attitude and the shower
of formic acid are chiefly of use against these parasitic foes: for when
an ichneumon-fly appears, the caterpillar assumes his "terrifying"
attitude the moment it touches him, and faces full round to the foe with
his false mask inflated. A very small quantity of the formic acid
Professor Poulton found sufficient to kill an ichneumon: and there can
be little doubt that this is its main object.
[Illustration: 9.--CATERPILLARS OF THE LOBSTER MOTH DEMONSTRATING IN
FORCE BEFORE THE HOSTILE BATTALIONS.]
The last of these "bluffing" caterpillars with which I shall deal here
is that of the Lobster Moth. In No. 9 you see a couple of these quaint
and unwieldy creatures "demonstrating" before an enemy, as if he were
the Sultan. The Lobster Moth in its larval stage frequents beech-trees,
and you will see in the illustration that the two represented are on a
twig of beech. When at rest, the caterpillar resembles a curled and
withered beech-leaf, and by this unconscious mimicry escapes detection.
But when discovered and roused to battle, oh, then he imitates the
action of the spider. He holds up his short front legs in a menacing
attitude, so as to suggest a pair of frightful gaping jaws: the four
long legs behind these he keeps wide apart and makes them quiver with
rage in the most alarming pantomimic indignation. His tail he turns
topsy-turvy over his head like a scorpion; while the forked appendages
at its end seem like frightful stings, with which he is just about to
inflict condign punishment on whoever has dared to disturb his quiet.
But it is all mere brag, though the whole effect is extremely
terrifying. The performance does not, indeed, mimic any particular
venomous beast, but it suggests most appalling and paralyzing
possibilities. Many of these queer attitudes, indeed, owe their
impressiveness just to their grotesque simulation of one knows not quite
what: they are not definite and special, they are worse than that; they
appeal to the imagination. And if only you reflect how afraid we often
feel of the most harmless insects, merely because they _look_ frightful,
you will readily understand that such vague appeals to the imagination
may be far more effectual than any real sting could ever be. We dread
the unknown even more than the painful.
The funniest of all these false pretences, however, is one which Hermann
Müller, I believe, was the first to point out in this same Lobster Moth
caterpillar. When very much bothered by ichneumon-flies (to whose
attacks it is particularly exposed), this bristling beast displays, for
the first time, two black patches on its side, till then concealed by a
triangular flap. Now, these patches closely resemble the sort of wound
made by the ichneumon when it deposits its eggs, so it is probable that
they serve to take in the assailant, who is thus led to think that
another fly of her own kind has been before her, and, therefore, that it
is no use laying her eggs where a previous parasite is already in
possession. There would not be enough Lobster Moth to feed _two_ hungry
ichneumon families. In fact, the caterpillar first begins by bluffing,
and says, "If you touch me, I bite!" then, finding the bluff
unsuccessful, it further pretends to throw up the sponge, and cries out
with a bounce: "Oh, if egg-laying is your game, _that's_ no good: I'm
already occupied!" For a combination of wiles, this crafty double game
probably "licks creation."
If the defenders are so cunning, however, the attackers can sometimes
turn the tables upon them. Animals that hunt often disguise themselves,
in order to avoid the notice of the prey, and so steal unobserved upon
their victims. Such tactics are like those of the Kaffirs, who cut bits
of bush, and then creep up slowly, slowly behind them, under cover of
the branches, upon the gnus or antelopes which they wish to slaughter.
In No. 10 we have one example of this method of hunting or stalking, as
pursued by the intelligent English grass-spider. All spiders, of course,
have eight legs, four on each side; but in most of the class, the
various pairs of legs are evenly distributed, so as to lie about the
body in a rough circle or something like it. The grass-spider, however,
has his own views on this important matter. His form and attitude are
quite peculiar. He lies in wait for his prey on the open, crouched
against a stem of grass, with his two front pairs of legs extended
before him, and his back pair behind, in an arrangement which is rather
linear than circular. This position makes him almost invisible--much
more invisible in real life, indeed, than you see him in the drawing;
for if he were represented as inconspicuous as he looks you would say
there was no spider there at all, only a naked grass-stem. The delusion
is heightened by his lines and colours: he is mostly green or greenish,
with narrow black or brown stripes which run more or less up and down
his body, instead of cross-wise as usual, so that they harmonize
beautifully with the up-and-down lines of the blades and stem in the
tuft which he inhabits. When he is pressed close against a bent of
grass, on the look-out for flies, it is almost impossible for the
quickest eye to distinguish him. Flies come near, never suspecting the
presence of their hereditary foe; as soon as they are close to him, the
grass-spider rushes out with a dash and secures them. His jaws are among
the most terrible in all his terrible race: they are large and
wide-spreading, with two rows of teeth on either side, and a pair of
long fangs of truly formidable proportions.
[Illustration: 10.--GRASS-SPIDER, IN AMBUSH FOR FLIES.]
In other ways, also, this particular spider is a clever fellow, for he
lives near water; but when the rains are heavy and there is likely to be
a flood, he shifts his quarters higher up the ground, and so escapes
impending inundation.
Deceptions and false pretences of this sort are somewhat less common
among plants than among animals; but still, they occur, and that not
infrequently. "What? Plants deceive?" you cry. "The innocent little
flowers? How can they do it? Surely that is impossible!" By no means. I
have watched plant life pretty closely for a good many years now, and
every year the conviction is forced upon me more and more profoundly
that whatever animals do, plants do almost equally. There is no vile
trick or ruse or stratagem that they cannot imitate: no base deception
that they will not practise. They lie and steal with the worst; they
hold out false baits for deluded insects, and hide real fly-traps with
honeyed words and sweet secretions.
As a good illustration among English plants, look at the Grass of
Parnassus, that beautiful, dishonest bog-herb, with glossy-green leaves
and pure white blossoms, which is considered the especial guerdon of
poets. I found a whole nest of it once in a swamp near Cromer, and
carried off a bunch of the lovely flowers as an appropriate offering to
Mr. Swinburne who was stopping at Sidestrand. Yet this poet's flower,
dainty and delicate as it is--you see in No. 11 its counterfeit
presentment--is not ashamed to deceive the poor bees and flies in a way
which the Heathen Chinee would have considered unsportsmanlike. It is a
sham, a commercial sham of the worst type. It lives for the most part on
wet moors among mountains, or else in the boggy hollows between blown
sand-hills by the sea: and when its milk-white flowers star the ground
in such spots, it forms one of the loveliest ornaments of our English
flora. But trust it not, oh butterfly: it is fooling thee! From a
distance, it looks as if it were full of honey; it advertises well: but
at close quarters 'tis a wooden nutmeg; it turns out to be nothing
better than an arrant humbug.
[Illustration: 11.--GRASS OF PARNASSUS, DISPLAYING AND ADVERTISING ITS
IMITATION HONEY.]
The deception is managed in this disgraceful fashion. Inside each petal
lies a curious ten or twelve-fingered organ, which is in reality an
abortive stamen. No. 12 shows you one such petal removed, with the false
honey-glands drawn on a larger scale than in the other illustration. The
ten-fingered stamen bears at its tip a number of translucent yellow
drops, which look like pure nectar. But they are nothing of the kind; I
regret to say, they are solid--solid--a commercial falsehood. They
glisten like drops: but they are mere glassy imitations; and they are
put there with intent to deceive, in order to attract flies and other
insects, which come to quaff the supposed nectar, and so unwittingly
fertilize the seeds, while they are muddling about perplexed among the
pretended honey-glands, without getting paid one sip for their toil and
trouble. This is, of course, a flagrant case of obtaining services under
false pretences; it deserves fourteen days' without the option of a
fine. As a rule, in similar cases, the flies are rewarded for their kind
offices as carriers by the merited wage of a drop of honey. But the
Grass of Parnassus, mendacious herb, pretends to be purveying a
specially fine quantity and quality of nectar, while in reality it
offers only a hard, glassy knob with nothing in it. This pays the plant,
of course, because the blossoms do not have to go on producing honey
fresh and fresh; a mere inexpensive show does just as well as the real
article: "Our customers like it!" but the language of the flies when
they discover the fraud is something just awful.
[Illustration 12.--A SINGLE PETAL, TO SHOW THE CHARACTER OF THE SHAM
HONEY.]
Nor is this by any means a solitary example of plant depravity. The
whole group of pitcher-plants, for instance, cruelly manure themselves
by means of living insects in the most treacherous fashion. These lovely
and wicked plants live, without exception, in wet and boggy soil, where
they cannot get enough animal matter for manure in the ordinary way by
the roots: so they lay themselves out instead to capture and absorb the
tissues of insects. For this horrid purpose, they twist their leaves
into deep pitchers which catch and hold the rain water, and so form
reservoirs to drown their prey. Then they entice insects by bright
colours to their traps, and allure them to enter by secreting honey at
the top of the pitcher. Hairs point downward inside; these allow the
flies to walk on to their fate, bribed as they go by lines of nectar:
but if they try to return, ah, then they find their mistake: the hairs
prevent them, after the fashion of a lobster-pot. Thus they walk on and
on till they reach the water, when they are swamped and clotted in a
decaying mass, from which the treacherous plant draws manure at last for
its own purposes. The pitchers are thus at once traps to catch animals,
and stomachs to digest them.
Another and still odder case of deceptiveness in plants is shown by a
curious group of South African flowers, the Hydaoras and Stapelias.
These queer and malodorous herbs have very large and rather handsome but
fleshy blossoms, an inch or two across, dappled and spotted just like
decaying meat. They live in the dry and almost desert region, where
carrion-flies abound. Such flies lay their eggs and hatch out their
grubs for the most part in half-eaten carcasses of antelopes or smaller
animals killed and in part devoured by lions and other beasts of prey.
So the flowers have taken to imitating dead meat. They are a lurid red
in colour, with livid livery patches, and they have a strong and
unpleasant smell of decaying animal matter. The flies, deceived by the
scent, flock to them to lay their eggs, and in so doing carry out the
real object of the plant by fertilizing the blossoms. But, of course,
the whole thing is a vile sham; for when the maggots hatch out, the
flower has died, and there is no food for them, so they perish of
starvation. Dr. Blackmore, of Salisbury, once gave me some of these
curious plants and flowers: I noticed that in the sunlight, where they
smelt just like decomposing meat, they attracted dozens of bluebottle
flies and other carrion insects.
Protective resemblance also occurs among plants: for in the same dry
South African region, where every green thing gets nibbled down in the
rainless season, certain ice-plants and milk-weeds have acquired the
trick of forming tubers or stems exactly like the pebbles among which
they grow: so that when the leaves die down in the dry weather, the
tuber is not distinguishable from the stones all round it. Such tubers
are really reservoirs of living material destined to carry the life of
the plant over the dead season: as soon as rain comes again, they put
forth fresh green leaves at once, and grow on after their sleep as if
nothing had happened. Even terrifying attitudes are not unknown in the
vegetable world: for one of the uses of the movements in the Sensitive
Plant is almost certainly to frighten animals. Browsing creatures that
come near the bushes in their native woods see the leaves shrink back
and curl up when touched, and are afraid to eat a tree that has so
evidently a spirit in it. The Squirting Cucumber of the Mediterranean,
again, alarms goats and cattle by discharging its ripe fruits
explosively in their faces the moment the stem is touched. In this case
the primary object is no doubt the dispersal of the seeds, which squirt
out elastically as the fruit jumps off; but to frighten browsing enemies
is a secondary advantage. There can be no question as to the reality of
the plant's hostile intention, because the fruits also contain a pungent
juice, which discharges itself at the same instant into the eyes of the
assailant. As I have received a volley of this irritating liquid more
than once in my own face (in the pursuit of science) I can testify
personally on the best of evidence that it is distinctly painful. The
tactics of the Squirting Cucumber in first frightening you, and then
injecting acrid juice into your eyes, are thus exactly similar to the
plan of action pursued by the angry larva of the Puss Moth.
_From Behind the Speaker's Chair._