The anonymous author of the observations on the termites of Ceylon, seems to have discovered a sentry-box in his nests. “I found,” says he, “in a very small cell in the middle of the solid mass, (a cell about half an inch in height, and very narrow,) a larva with an enormous head. Two of these individuals were in the same cell; one of the two seemed placed as sentinel at the entrance of the cell. I amused myself by forcing the door two or three times; the sentinel immediately appeared, and only retreated when the door was on the point of being stopped up, which was done by the labourers.”
The Green Ants.—Captain Cook gives the following account of a very peculiar kind of ants, which he met with at Botany Bay.—“They are as green as a leaf. They live upon trees, where they build their nests. The nests are of a very curious structure: they are formed by bending down several of the leaves, each of which is as broad as a man’s hand; they glue the points of them together, so as to form a purse. The viscus used for this purpose is an animal juice, which nature has enabled them to elaborate. Their method of first bending down the leaves, our naturalists had not an opportunity of observing; but they saw thousands uniting all their strength to hold them in this position, while other busy multitudes were employed within, in applying the gluten that was to prevent their returning back. To satisfy themselves that the leaves were bent and held down by the efforts of these diminutive artificers, our people disturbed them in their work, and, as soon as they were driven from their station, the leaves on which they were employed sprang up with a force much greater than they could have thought them able to conquer, by any combination of their strength.”
The Visiting Ants.—At Paramaribo, a Dutch colony in the province of Surinam, there is a species of ants, which the Portuguese call visiting ants: they march in troops, and as soon as they appear, all the coffers and chests of drawers are laid open, which they clear of rats, mice, and a peculiar sort of insect in that country, called cackerlacks, and of other noxious animals. If any one chance to molest them, they fall upon him, and tear in pieces his stockings and shoes. Their visits are rare; and sometimes they do not appear for three years.—Templeman’s Obs. vol. i. p. 36.
We conclude this chapter with an account of The Ant-Lion.—There is no insect more remarkable for its dexterity than the ant-lion, though its figure announces nothing extraordinary. It nearly resembles the woodlouse; its body being provided with six feet, composed of several membranous rings, and terminated in a point. Its head, flat and square, is armed with two moveable crooked horns, whose singular structure shews how admirable Nature is, even in the least of her works.
This insect is the most subtle and dangerous enemy the ant has; the plans which he forms to ensnare his prey, are very ingenious. He mines a portion of land in the form of a funnel, at the bottom of which he waits to seize the ants, which coming by chance to the edge of the precipice, are thence hurried down to their merciless foe. In order to dig it, he first traces in the sand a circular furrow, whose circumference forms precisely the mouth of the funnel, the diameter of which is always equal to the depth he gives to his ditch. When he has determined the space of this opening, and traced the first furrow, he immediately digs a second, concentric to the other, in order to throw out all the sand contained in the first circle. He makes all these operations with his head, which serves him instead of a shovel, and its flat and square form admirably adapts it to this purpose. He also takes some sand with one of his fore feet, to throw it beyond the first furrow; and this work is repeated till the insect has reached a certain depth of sand. Sometimes, in digging, he meets with grains of sand larger than usual, or with little bits of dry earth, which he will not suffer to remain in his tunnel; of these he disencumbers himself by a sudden and well-timed manœuvre of his head. Should he find particles yet larger, he endeavours to push them away with his back, and he is so assiduous in this labour, that he repeats it six or seven times.
At length the ant-lion comes to collect the fruits of his toil. His nets being once well laid, he has nothing to do but to put himself on the watch; accordingly, immoveable and concealed at the bottom of the ditch which he has dug, he patiently waits for the prey which he cannot pursue. If some unhappy ant is inadvertently drawn to the borders of this fatal precipice, she is almost sure to roll down to the bottom, because the brink is made sloping, and thus the sand giving way beneath her feet, she is forced to follow the dangerous declivity till she falls into the power of her destroyer, who, by means of his horns, draws her under the sand, and feasts upon her blood. When he has sucked all the juices from her body, he contrives to eject from his habitation the dry and hollow carcase, repairs any damage his trench may have sustained, and puts himself again in ambush. He does not always succeed in seizing his prey at the moment of its fall; it frequently escapes him, and endeavours to remount the funnel; but then the ant-lion works with his head, and causes a shower of sand to descend upon his captive, and precipitate it once more to the bottom.
All the actions of this little animal display an art so extraordinary, that we might often examine them without being wearied. The ant-lion employs itself in preparing trenches even before having seen the animal which they are to ensnare, and which is to serve it for nourishment; and yet its actions are regulated in a manner the best adapted to accomplish these purposes.
How would an animal, so destitute of agility, have been able to entrap its prey more easily than by digging in a moveable sand, and giving a sloping declivity to this funnel? What better stratagem could it have devised for recovering the ants which were on the point of escaping even from this skilfully constructed snare, than in overwhelming them with showers of sand, and thus cutting off all hopes of a retreat? All its actions have fixed principles by which they are directed. The trench must be dug in the sand, or it could not answer the desired purpose; and it must, according to the structure of its body, work backwards, using its horns like a pair of pincers, in order to throw the sand over the brink of the funnel. The instinct which governs this insect, discovers to us a First Cause, whose intelligence has foreseen and ordained every thing that was necessary for the preservation and well-being of such an animal.