THE EMPUSA
The sea, life’s first foster-mother, still preserves in her depths many
of those singular and incongruous shapes which were the earliest
attempts of the animal kingdom; the land, less fruitful, but with more
capacity for progress, has almost wholly lost the strange forms of
other days. The few that remain belong especially to the series of
primitive insects, insects exceedingly limited in their industrial
powers and subject to very summary metamorphoses, if to any at all. In
my district, in the front rank of those entomological anomalies which
remind us of the denizens of the old coal-forests, stand the Mantidæ,
including the Praying Mantis, so curious in habits and structure. Here
also is the Empusa (E. pauperata, Latr.), the subject of this chapter.
Her larva is certainly the strangest creature among the terrestrial
fauna of Provence: a slim, swaying thing of so fantastic an appearance
that uninitiated fingers dare not lay hold of it. The children of my
neighbourhood, impressed by its startling shape, call it “the
Devilkin.” In their imaginations, the queer little creature savours of
witchcraft. One comes across it, though always sparsely, in spring, up
to May; in autumn; and sometimes in winter, if the sun be strong. The
tough grasses of the wastelands, the stunted bushes which catch the sun
and are sheltered from the wind by a few heaps of stones are the chilly
Empusa’s favourite abode.
Let us give a rapid sketch of her. The abdomen, which always curls up
so as to join the back, spreads paddlewise and twists into a crook.
Pointed scales, a sort of foliaceous expansions arranged in three rows,
cover the lower surface, which becomes the upper surface because of the
crook aforesaid. The scaly crook is propped on four long, thin stilts,
on four legs armed with knee-pieces, that is to say, carrying at the
end of the thigh, where it joins the shin, a curved, projecting blade
not unlike that of a cleaver.
Above this base, this four-legged stool, rises, at a sudden angle, the
stiff corselet, disproportionately long and almost perpendicular. The
end of this bust, round and slender as a straw, carries the
hunting-trap, the grappling limbs, copied from those of the Mantis.
They consist of a terminal harpoon, sharper than a needle, and a cruel
vice, with jaws toothed like a saw. The jaw formed by the arm proper is
hollowed into a groove and carries on either side five long spikes,
with smaller indentations in between. The jaw formed by the fore-arm is
similarly furrowed, but its double saw, which fits into the groove of
the upper arm when at rest, is formed of finer, closer and more regular
teeth. The magnifying-glass reveals a score of equal points in each
row. The machine only lacks size to be a fearful implement of torture.
The head is in keeping with this arsenal. What a queer-shaped head it
is! A pointed face, with walrus moustaches furnished by the palpi;
large goggle eyes; between them, a dirk, a halberd blade; and, on the
forehead, a mad, unheard-of thing: a sort of tall mitre, an extravagant
head-dress that juts forward, spreading right and left into peaked
wings and cleft along the top. What does the Devilkin want with that
monstrous pointed cap, than which no wise man of the East, no
astrologer of old ever wore a more splendiferous? This we shall learn
when we see her out hunting.
The dress is commonplace; grey tints predominate. Towards the end of
the larval period, after a few moultings, it begins to give a glimpse
of the adult’s richer livery and becomes striped, still very faintly,
with pale-green, white and pink. Already the two sexes are
distinguished by their antennæ. Those of the future mothers are
thread-like; those of the future males are distended into a spindle at
the lower half, forming a case or sheath whence graceful plumes will
spring at a later date.
Behold the creature, worthy of a Callot’s [36] fantastic pencil. If you
come across it in the bramble-bushes, it sways upon its four stilts, it
wags its head, it looks at you with a knowing air, it twists its mitre
round and peers over its shoulder. You seem to read mischief in its
pointed face. You try to take hold of it. The imposing attitude ceases
forthwith, the raised corselet is lowered and the creature makes off
with mighty strides, helping itself along with its fighting-limbs,
which clutch the twigs. The flight need not last long, if you have a
practised eye. The Empusa is captured, put into a screw of paper, which
will save her frail limbs from sprains, and lastly penned in a
wire-gauze cage. In this way, in October, I obtain a flock sufficient
for my purpose.
How to feed them? My Devilkins are very little; they are a month or two
old at most. I give them Locusts suited to their size, the smallest
that I can find. They refuse them. Nay more, they are frightened of
them. Should a thoughtless Locust meekly approach one of the Empusæ,
suspended by her four hind-legs to the trellised dome, the intruder
meets with a bad reception. The pointed mitre is lowered; and an angry
thrust sends him rolling. We have it: the wizard’s cap is a defensive
weapon, a protective crest. The Ram charges with his forehead, the
Empusa butts with her mitre.
But this does not mean dinner. I serve up the House-fly, alive. She is
accepted, without hesitation. The moment that the Fly comes within
reach, the watchful Devilkin turns her head, bends the stalk of her
corselet slantwise and, flinging out her forelimb, harpoons the Fly and
grips her between her two saws. No Cat pouncing upon a Mouse could be
quicker.
The game, however small, is enough for a meal. It is enough for the
whole day, often for several days. This is my first surprise: the
extreme abstemiousness of these savagely-armed insects. I was prepared
for ogres: I find ascetics satisfied with a meagre collation at rare
intervals. A Fly fills their belly for twenty-four hours at least.
Thus passes the late autumn: the Empusæ, more and more temperate from
day to day, hang motionless from the wire gauze. Their natural
abstinence is my best ally, for Flies grow scarce; and a time comes
when I should be hard put to it to keep the menageries supplied with
provisions.
During the three winter months, nothing stirs. From time to time, on
fine days, I expose the cage to the sun’s rays, in the window. Under
the influence of this heat-bath, the captives stretch their legs a
little, sway from side to side, make up their minds to move about, but
without displaying any awakening appetite. The rare Midges that fall to
my assiduous efforts do not appear to tempt them. It is a rule for them
to spend the cold season in a state of complete abstinence.
My cages tell me what must happen outside, during the winter. Ensconced
in the crannies of the rockwork, in the sunniest places, the young
Empusæ wait, in a state of torpor, for the return of the hot weather.
Notwithstanding the shelter of a heap of stones, there must be painful
moments when the frost is prolonged and the snow penetrates little by
little into the best-protected crevices. No matter: hardier than they
look, the refugees escape the dangers of the winter season. Sometimes,
when the sun is strong, they venture out of their hiding-place and come
to see if spring be nigh.
Spring comes. We are in March. My prisoners bestir themselves, change
their skin. They need victuals. My catering difficulties recommence.
The House-fly, so easy to catch, is lacking in these days. I fall back
upon earlier Diptera: Eristales, or Drone-flies. The Empusa refuses
them. They are too big for her and can offer too strenuous a
resistance. She wards off their approach with blows of her mitre.
A few tender morsels, in the shape of very young Grasshoppers, are
readily accepted. Unfortunately, such wind-falls do not often find
their way into my sweeping-net. Abstinence becomes obligatory until the
arrival of the first Butterflies. Henceforth, Pieris brassicæ, the
White Cabbage Butterfly, will contribute the greater portion of the
victuals.
Let loose in the wire cage, the Pieris is regarded as excellent game.
The Empusa lies in wait for her, seizes her, but releases her at once,
lacking the strength to overpower her. The Cabbage Butterfly’s great
wings, beating the air, give her shock after shock and compel her to
let go. I come to the weakling’s assistance and cut the wings of her
prey with my scissors. The maimed ones, still full of life, clamber up
the trelliswork and are forthwith grabbed by the Empusæ, who, in no way
frightened by their protests, crunch them up. The dish is to their
taste and, moreover, plentiful, so much so that there are always some
despised remnants.
The head only and the upper portion of the breast are devoured: the
rest—the plump abdomen, the best part of the thorax, the legs and
lastly, of course, the wing-stumps—is flung aside untouched. Does this
mean that the tenderest and most succulent morsels are chosen? No, for
the belly is certainly more juicy; and the Empusa refuses it, though
she eats up her House-fly to the last particle. It is a strategy of
war. I am again in the presence of a neck-specialist as expert as the
Mantis herself in the art of swiftly slaying a victim that struggles
and, in struggling, spoils the meal.
Once warned, I soon perceive that the game, be it Fly, Locust,
Grasshopper or Butterfly, is invariably struck in the neck, from
behind. The first bite is aimed at the point containing the cervical
ganglia and produces sudden death or immobility. Complete inertia will
leave the consumer in peace, the essential condition of every
satisfactory repast.
The Devilkin, therefore, frail though she be, possesses the secret of
immediately destroying the resistance of her prey. She bites at the
back of the neck first, in order to give the finishing stroke. She goes
on nibbling around the original attacking-point. In this way, the
Butterfly’s head and the upper part of the breast are disposed of. But,
by that time, the huntress is surfeited: she wants so little! The rest
lies on the ground, disdained, not for lack of flavour, but because
there is too much of it. A Cabbage Butterfly far exceeds the capacity
of the Empusa’s stomach. The Ants will benefit by what is left.
There is one other matter to be mentioned, before observing the
metamorphosis. The position adopted by the young Empusæ in the
wire-gauze cage is invariably the same from start to finish. Gripping
the trelliswork by the claws of its four hind-legs, the insect occupies
the top of the dome and hangs motionless, back downwards, with the
whole of its body supported by the four suspension-points. If it wishes
to move, the front harpoons open, stretch out, grasp a mesh and draw it
to them. When the short walk is over, the lethal arms are brought back
against the chest. One may say that it is nearly always the four
hind-shanks which alone support the suspended insect.
And this reversed position, which seems to us so trying, lasts for no
short while: it is prolonged, in my cages, for ten months without a
break. The Fly on the ceiling, it is true, occupies the same attitude;
but she has her moments of rest: she flies, she walks in a normal
posture, she spreads herself flat in the sun. Besides, her acrobatic
feats do not cover a long period. The Empusa, on the other hand,
maintains her curious equilibrium for ten months on end, without a
break. Hanging from the trelliswork, back downwards, she hunts, eats,
digests, dozes, casts her skin, undergoes her transformation, mates,
lays her eggs and dies. She clambered up there when she was still quite
young; she falls down, full of days, a corpse.
Things do not happen exactly like this under natural conditions. The
insect stands on the bushes back upwards; it keeps its balance in the
regular attitude and turns over only in circumstances that occur at
long intervals. The protracted suspension of my captives is all the
more remarkable inasmuch as it is not at all an innate habit of their
race.
It reminds one of the Bats, who hang, head downwards, by their
hind-legs from the roof of their caves. A special formation of the toes
enables birds to sleep on one leg, which automatically and without
fatigue clutches the swaying bough. The Empusa shows me nothing akin to
their contrivance. The extremity of her walking-legs has the ordinary
structure: a double claw at the tip, a double steelyard-hook; and that
is all.
I could wish that anatomy would show me the working of the muscles and
nerves in those tarsi, in those legs more slender than threads, the
action of the tendons that control the claws and keep them gripped for
ten months, unwearied in waking and sleeping. If some dexterous scalpel
should ever investigate this problem, I can recommend another, even
more singular than that of the Empusa, the Bat and the bird. I refer to
the attitude of certain Wasps and Bees during the night’s rest.
An Ammophila with red fore-legs (A. holosericea) [37] is plentiful in
my enclosure towards the end of August and selects a certain
lavender-border for her dormitory. At dusk, especially after a stifling
day, when a storm is brewing, I am sure to find the strange sleeper
settled there. Never was more eccentric attitude adopted for a night’s
rest! The mandibles bite right into the lavender-stem. Its square shape
supplies a firmer hold than a round stalk would do. With this one and
only prop, the animal’s body juts out stiffly, at full length, with
legs folded. It forms a right angle with the supporting axis, so much
so that the whole weight of the insect, which has turned itself into
the arm of a lever, rests upon the mandibles.
The Ammophila sleeps extended in space by virtue of its mighty jaws. It
takes an animal to think of a thing like that, which upsets all our
preconceived ideas of repose. Should the threatening storm burst,
should the stalk sway in the wind, the sleeper is not troubled by her
swinging hammock; at most, she presses her fore-legs for a moment
against the tossed mast. As soon as equilibrium is restored, the
favourite posture, that of the horizontal lever, is resumed. Perhaps
the mandibles, like the bird’s toes, possess the faculty of gripping
tighter in proportion to the rocking of the wind.
The Ammophila is not the only one to sleep in this singular position,
which is copied by many others—Anthidia, [38] Odyneri, [39] Euceræ
[40]—and mainly by the males. All grip a stalk with their mandibles and
sleep with their bodies outstretched and their legs folded back. Some,
the stouter species, allow themselves to rest the tip of their arched
abdomen against the pole.
This visit to the dormitory of certain Wasps and Bees does not explain
the problem of the Empusa; it sets up another one, no less difficult.
It shows us how deficient we are in insight, when it comes to
differentiating between fatigue and rest in the cogs of the animal
machine. The Ammophila, with the static paradox afforded by her
mandibles; the Empusa, with her claws unwearied by ten months’ hanging,
leave the physiologist perplexed and make him wonder what really
constitutes rest. In absolute fact, there is no rest, apart from that
which puts an end to life. The struggle never ceases; some muscle is
always toiling, some nerve straining. Sleep, which resembles a return
to the peace of non-existence, is, like waking, an effort, here of the
leg, of the curled tail; there of the claw, of the jaws.
The transformation is effected about the middle of May and the adult
Empusa makes her appearance. She is even more remarkable in figure and
attire than the Praying Mantis. Of her youthful eccentricities, she
retains the pointed mitre, the saw-like arm-guards, the long bust, the
knee-pieces, the three rows of scales on the lower surface of the
belly; but the abdomen is now no longer twisted into a crook and the
animal is comelier to look upon. Large pale-green wings, pink at the
shoulder and swift in flight in both sexes, cover the belly, which is
striped white and green underneath. The male, the dandy sex, adorns
himself with plumed antennæ, like those of certain Moths, the Bombyx
tribe. In respect of size, he is almost the equal of his mate.
Save for a few slight structural details, the Empusa is the Praying
Mantis. The peasant confuses them. When, in spring, he meets the mitred
insect, he thinks he sees the common Prègo-Diéu, who is a daughter of
the autumn. Similar forms would seem to indicate similarity of habits.
In fact, led away by the extraordinary armour, we should be tempted to
attribute to the Empusa a mode of life even more atrocious than that of
the Mantis. I myself thought so at first; and any one, relying upon
false analogies, would think the same. It is a fresh error: for all her
warlike aspect, the Empusa is a peaceful creature that hardly repays
the trouble of rearing.
Installed under the gauze bell, whether in assemblies of half-a-dozen
or in separate couples, she at no time loses her placidity. Like the
larva, she is very abstemious and contents herself with a Fly or two as
her daily ration.
Big eaters are naturally quarrelsome. The Mantis, bloated with Locusts,
soon becomes irritated and shows fight. The Empusa, with her frugal
meals, does not indulge in hostile demonstrations. There is no strife
among neighbours nor any of those sudden unfurlings of the wings so
dear to the Mantis when she assumes the spectral attitude and puffs
like a startled Adder; never the least inclination for those cannibal
banquets whereat the sister who has been worsted in the fight is
devoured. Such atrocities are here unknown.
Unknown also are tragic nuptials. The male is enterprising and
assiduous and is subjected to a long trial before succeeding. For days
and days, he worries his mate, who ends by yielding. Due decorum is
preserved after the wedding. The feathered groom retires, respected by
his bride, and does his little bit of hunting, without danger of being
apprehended and gobbled up.
The two sexes live together in peace and mutual indifference until the
middle of July. Then the male, grown old and decrepit, takes counsel
with himself, hunts no more, becomes shaky in his walk, creeps down
from the lofty heights of the trellised dome and at last collapses on
the ground. His end comes by a natural death. And remember that the
other, the male of the Praying Mantis, ends in the stomach of his
gluttonous spouse.
The laying follows close upon the disappearance of the males. The
Empusa, when about to build her nest, has not the round belly of the
Praying Mantis, rendered heavy and inactive by her fertility. Her
slender figure, still capable of flight, announces a scanty progeny.
Her nest, fixed upon a straw, a twig, a chip of stone, is quite as
small a structure as that of the dwarf Mantis (Ameles decolor) and
measures two-fifths of an inch, at most, in length. The general shape
is that of a trapezoid, of which the shorter sides are, respectively,
sloping and slightly convex. As a rule, the sloping side is surmounted
by a thread-like appendage, similar to the final spur of the nests of
the Mantis and the Ameles, but finer in appearance. This is the last
drop of viscous matter, dried and drawn out. Builders, when their work
is finished, crown the edifice with a green bough and coloured
streamers. In much the same way, the Mantis tribe set up a mast on the
completed nest.
A very thin grey-wash, formed of dried foam, covers the Empusa’s work,
especially on the upper surface. Under this delicate glaze, which is
easily rubbed off, the fundamental substance appears, homogeneous,
horny, pale-red. Six or seven hardly-perceptible furrows divide the
sides into curved sections.
After the hatching, a dozen round orifices open on the top of the
building, in two alternate rows. These are the exit-doors for the young
larvæ. The slightly projecting rim is continued from each aperture to
the next in a sort of ribbon with a double row of alternating loops. It
is obvious that the windings of this ribbon are the result of an
oscillating movement of the ovipositor in labour. Those exit-holes, so
regular in shape and arrangement, completed by the lateral ribs of the
nest, present the appearance of two dainty mouth-organs placed in
juxtaposition. Each of them corresponds with a cell containing two
eggs. The eggs in all, therefore, amount to about a couple of dozen.
I have not seen the hatching. I do not know whether, as in the Praying
Mantis, it is preceded by a transition-stage adapted to facilitate the
delivery. It may easily be that there is nothing of the kind, since
everything is so well-prepared for the exit. Above the cells is a very
short exit-hall, free of any obstacle. It is closed merely by a small
quantity of frothy, crumbly matter, which will readily yield to the
mandibles of the new-born larvæ. With this wide passage leading to the
outer air, long legs and slender antennæ cease to be embarrassing
appendages; and the tiny creature might well have the free use of them
from the moment of leaving the egg, without going through the primary
larval stage. Not having seen for myself, I merely mention the probable
course of things.
One word more on comparative manners. The Mantis goes in for battle and
cannibalism; the Empusa is peaceable and respects her kind. To what
cause are these profound moral differences due, when the organic
structure is the same? Perhaps to the difference of diet. Frugality, in
fact, softens character, in animals as in men; gross feeding brutalizes
it. The gormandizer gorged with meat and strong drink, a fruitful
source of savage outbursts, could not possess the gentleness of the
ascetic who dips his bread into a cup of milk. The Mantis is that
gormandizer, the Empusa that ascetic.
Granted. But whence does the one derive her voracious appetite, the
other her temperate ways, when it would seem as though their almost
identical structure ought to produce an identity of needs? These
insects tell us, in their fashion, what many have already told us: that
propensities and aptitudes do not depend exclusively upon anatomy; high
above the physical laws that govern matter rise other laws that govern
instincts.