Crickets of all kinds, butterflies, bees, large flies of many species, and other insects of moderate size: such is the prey that we habitually find in the embrace of the murderous arms of the Mantis. But in my cages I have never known the audacious huntress to recoil before any other insect. Grey cricket, Decticus, Epeirus or Truxalis, sooner or later all are harpooned, held motionless between the saw-edges of the arms, and deliciously crunched at leisure. The process deserves a detailed description.
At the sight of a great cricket, which thoughtlessly approaches along the wire-work of the cover, the Mantis, shaken by a convulsive start, suddenly assumes a most terrifying posture. An electric shock would not produce a more immediate result. The transition is so sudden, the mimicry so threatening, that the unaccustomed observer will draw back his hand, as though at some unknown danger. Seasoned as I am, I myself must confess to being startled on occasions when my thoughts have been elsewhere. The creature spreads out like a fan actuated by a spring, or a fantastic Jack-in-the-box.
The wing-covers open, and are thrust obliquely aside; the wings spring to their full width, standing up like parallel screens of transparent gauze, forming a pyramidal prominence which dominates the back; the end of the abdomen curls upwards crosier-wise, then falls and unbends itself with a sort of swishing noise, a pouf! pouf! like the sound emitted by the feathers of a strutting turkey-cock. One is reminded of the puffing of a startled adder.
Proudly straddling on its four hind-claws, the insect holds its long body almost vertical. The murderous fore-limbs, at first folded and pressed against one another on the thorax, open to their full extent, forming a cross with the body, and exhibiting the axillæ ornamented with rows of pearls, and a black spot with a central point of white. These two eyes, faintly recalling those of the peacock's tail, and the fine ebony embossments, are part of the blazonry of conflict, concealed upon ordinary occasions. Their jewels are only assumed when they make themselves terrible and superb for battle.
Motionless in its weird position, the Mantis surveys the acridian, its gaze fixed upon it, its head turning gently as on a pivot as the other changes place. The object of this mimicry seems evident; the Mantis wishes to terrorise its powerful prey, to paralyse it with fright; for if not demoralised by fear the quarry might prove too dangerous.
Does it really terrify its prey? Under the shining head of the Decticus, behind the long face of the cricket, who is to say what is passing? No sign of emotion can reveal itself upon these immovable masks. Yet it seems certain that the threatened creature is aware of its danger. It sees, springing up before it, a terrible spectral form with talons outstretched, ready to fall upon it; it feels itself face to face with death, and fails to flee while yet there is time. The creature that excels in leaping, and might so easily escape from the threatening claws, the wonderful jumper with the prodigious thighs, remains crouching stupidly in its place, or even approaches the enemy with deliberate steps.[2]
It is said that young birds, paralysed with terror by the gaping mouth of a serpent, or fascinated by its gaze, will allow themselves to be snatched from the nest, incapable of movement. The cricket will often behave in almost the same way. Once within reach of the enchantress, the grappling-hooks are thrown, the fangs strike, the double saws close together and hold the victim in a vice. Vainly the captive struggles; his mandibles chew the air, his desperate kicks meet with no resistance. He has met with his fate. The Mantis refolds her wings, the standard of battle; she resumes her normal pose, and the meal commences.
In attacking the Truxalis and the Ephippigera, less dangerous game than the grey cricket and the Decticus, the spectral pose is less imposing and of shorter duration. It is often enough to throw forward the talons; this is so in the case of the Epeirus, which is seized by the middle of the body, without a thought of its venomous claws. With the smaller crickets, which are the customary diet in my cages as at liberty, the Mantis rarely employs her means of intimidation; she merely seizes the heedless passer-by as she lies in wait.
When the insect to be captured may present some serious resistance, the Mantis is thus equipped with a pose which terrifies or perplexes, fascinates or absorbs the prey, while it enables her talons to strike with greater certainty. Her gins close on a demoralised victim, incapable of or unready for defence. She freezes the quarry with fear or amazement by suddenly assuming the attitude of a spectre.
The wings play an important part in this fantastic pose. They are very wide, green on the outer edge, but colourless and transparent elsewhere. Numerous nervures, spreading out fan-wise, cross them in the direction of their length. Others, transversal but finer, cut the first at right angles, forming with them a multitude of meshes. In the spectral attitude the wings are outspread and erected in two parallel planes which are almost in contact, like the wings of butterflies in repose. Between the two the end of the abdomen rapidly curls and uncurls. From the rubbing of the belly against the network of nervures proceeds the species of puffing sound which I have compared to the hissing of an adder in a posture of defence. To imitate this curious sound it is enough rapidly to stroke the upper face of an outstretched wing with the tip of the finger-nail.