earth, are arranged in a semi-circular wall, | tice either of the workers or the works. They the termite, now assisted by three or four are posted there in fact as sentries, and there others, standing in the middle between the they stand, or promenade about, at the mouth sheltering wall and the tree and working of every tunnel, like sister Ann, to see if briskly with head and mandible to strengthen anybody is coming. Sometimes somebody the position. The wall in fact forms a does come in the shape of another ant-the small moon-rampart, and as it grows higher real ant this time, not the defenceless Neurand higher it soon becomes evident that it opteron, but some valiant and belted knight is going to grow from a low battlement into from the warlike Formicida. Singly, or in a long perpendicular tunnel running up the troops, this rapacious little insect, fearless in side of the tree. The workers, safely ensconced its chitinous coat of mail, charges down the inside, are now carrying up the structure tree-trunk, its antennæ waving defiance to with great rapidity, disappearing in turn as the enemy and its cruel mansoon as they have laid their stone and rush-dibles thirsting for termite ing off to bring up another. The way in blood. The worker white ant which the building is done is extremely is a poor defenceless creature, curious and one could watch the movement and, blind and unarmed, would of these wonderful little masons by the hour. fall an immediate prey to Each stone as it is brought to the top is first these well-drilled banditti, who of all covered with mortar. Of course, forage about in every tropical without this the whole tunnel would crumble forest in unnumbered legion. into dust before reaching the height of half- But at the critical moment, an-inch; but the termite pours over the stone like Goliath from the Philistines, the soldier a moist sticky secretion, turning the grain termite advances to the fight. With a few round and round with its mandibles until the sweeps of its scythe-like jaws it clears the whole is covered with slime. Then it places ground, and while the attacking party is carthe stone with great care upon the top of the rying off its dead, the builders, unconscious wall, works it about vigorously for a moment of the fray, quietly continue their work. To or two till it is well jammed into its place, every hundred workers in a white ant colony, and then starts off instantly for another load. which numbers many thousands of individuals, Peering over the growing wall one soon there are perhaps two of these fighting-men. discovers one, two, or more termites of a The division of labour here is very wonderful, somewhat larger build, considerably longer, and the fact that besides these two specialised and with a very different arrangement of the forms there are in every nest two other kinds parts of the head and especially of the man- of the same insect, the kings and queens, Fig. 2.-Soldier shows the remarkable height to which civilisation in these communities has attained. But where is this tunnel going to, and what object have the insects in view in ascending this lofty tree? Thirty feet from the ground, across innumerable forks, at the end of a long branch are a few feet of dead wood. How the ants know it is there, how they know its sap has dried up, and that it is now fit for the termites' food, is a mystery. Possibly they do not know, and are only prospecting on the chance. The fact that they sometimes make straight for the decaying limb argues in these instances a kind of definite instinct; but, on the other hand, the fact that in most cases the whole tree, in every branch and limb, is covered with termite tunnels, would show perhaps that they work most commonly on speculation, while the number of abandoned tunnels, ending on а sound branch in a cul de sac, proves how often they must suffer the usual disappointments of all such adven turers. The "Useful to the sportsman." extent to which these insects carry on their | a fallen branch is seen. Rocky Moun tains or of the Western States, the broken branches and fallen trunks strewing the ground breasthigh with all sorts of decaying litter, frequently make locomotion impossible. To attempt to ride through these western forests, with their meshwork of interlocked branches and decaying trunks, is often out of the question, and one has to dismount and drag his horse after him as if he were clambering through a wood-yard. But in an African forest not One is struck at tunnelling is quite incredible until one has first at a certain clean look about the great seen it in nature with his own eyes. The forests of the interior, a novel and unactunnels are perhaps about the thickness of a small-sized gas-pipe, but there are junctions here and there of large dimensions, and occasionally patches of earth-work are found embracing nearly the whole trunk for some feet. The outside of these tunnels, which are never quite straight, but wander irregularly along stem and branch, resembles in texture a coarse sand-paper; and the colour, although this naturally varies with the soil, countable cleanness, as if the forest-bed was carefully swept and dusted daily by unseen elves. And so, indeed, it is. Scavengers of a hundred kinds remove decaying animal matter-from the carcase of the fallen elephant to the broken wing of a gnateating it, or carrying it out of sight, and burying it in the deodorising earth. And these countless millions of termites perform a similar function for the vegetable fork, the ligneous tis- There is the from which the its way outward and onward, leaving a thin tube of the outer wood to the last as props to the mine till they have finished the main excavation. When a fallen trunk lying upon the ground is the object of attack, the outer cylinder is frequently left quite intact, and it is only when one tries to drag it off to his camp-fire that he finds to his disgust that he is dealing with a mere hollow tube a few lines in thickness filled up with mud. But the works above ground represent only a part of the labours of these slowmoving but most industrious of creatures. The arboreal tubes are only the prolongation of a much more elaborate system of subterranean tunnels (Fig. 4) which extend over large areas and mine the earth sometimes to a depth of many feet or even yards. The material excavated from these underground galleries and from the succession of domed chambers-used as nurseries and granaries-to which they lead, has to be thrown out upon the surface. And it is from these materials that the huge ant-hills are reared, which form so distinctive a feature of the African landscape. These heaps and mounds are so conspicuous that they may be seen for miles, and so numerous are they and so useful as cover to the sports Fig. 4.-Galleries in White Ants' Nest. outer bark untouched, or more usually replacing it with grains of earth atom by atom as they eat it away. The inner bark is gnawed off likewise as they go along, but the woody tissue beneath is allowed to remain to form a protective sheath for the second company who begin work at the centre. This second contingent eats man, that without them in certain dis tricts hunting would be impossible. The first things, indeed, to strike the traveller in entering the interior are the mounds of the white ant, now dotting the plain in groups like a small cemetery, now rising into mounds singly or in clusters, each thirty or forty feet in diameter, and ten or fifteen in height, or again standing out against the sky like obelisks, their bare sides carved and fluted into all sorts of fantastic shapes (pages 296, 297, 300). In India these antheaps seldom attain a height of more than a couple of feet, but in Central Africa they form veritable hills, and contain many tons of earth. The brick houses of the Scotch mission-station on Lake Nyassa have all been built out of a single ants' nest, and the quarry from which the material has been derived forms a pit beside the settlement some dozen feet in depth. A supply of bricks as large again could probably still be taken from this convenient depôt, and the missionaries on Lake Tanganyika and onwards to Victoria Nyanza have been similarly indebted to the labours of the termites. In South Africa the Zulus and Kaffirs pave all their huts with white-ant earth; and during the Boer war our troops in Praetoria, by scooping out the interior from the smaller beehiveshaped ant-heaps, and covering the top with clay, constantly used them as ovens. These ant-heaps may be said to abound over the whole interior of Africa, and there are three or four distinct varieties. The most peculiar, as well as the most ornate, is a small variety from one to two feet in height, which occurs in myriads along the shores of Lake Tanganyika. It is built in symmetrical tiers, and resembles a pile of small rounded hats, one above another, the rims depending like eaves, and sheltering the body of the hill from rain. To estimate the amount of earth per acre raised from the water-line of the subsoil by white ants would not in some districts be an impossible task, and it would be found probably that the quantity at least equalled that manipulated annually in temperate regions by the earth-worm. These mounds, however, are more than mere waste-heaps. Like the corresponding region underground they are built into a meshwork of tunnels, galleries, and chambers, where the social interests of the community are attended to. The most spacious of these chambers, usually far underground, is very properly allocated to the head of the society, the queen. The queen-termite (Fig. 5) is a very rare insect, and as there are seldom more than one, or at most two, to a colony, and as the royal apartments are hidden far in the earth, few persons have ever seen a queen, and indeed most, if they did happen to come across it, from its very singular appearance would refuse to believe that it had any connection with white ants. It possesses, indeed, the true termite head (Figs. 6, 7), but there the resemblance to the other members of the family stops, for the size of the head bears about the same proportion to the Fig. 6.-Head of Queen magnified. Fig. 7.-Undeveloped winged female. rest of the body as does the tuft on his Glengarry bonnet to a six-foot Highlander. The phenomenal corpulence of the royal body in the case of the queen-termite is possibly due in part to want of exercise, for once seated upon her throne she never stirs to the end of her days. She lies there, a large loathsome cylindrical package, two or three inches long, in shape like a sausage, and as white as a bolster. Her one duty in life is to lay eggs (Fig. 8), and it must be confessed she discharges her function with complete success, for in a single day her progeny often amounts to many thousands, and for months this enormous fecundity never slackens. The body increases slowly in size, and through the transparent skin the longfolded ovary may be seen, with the eggs, impelled by a peristaltic motion, passing onward for delivery to the workers who are waiting to carry them to the nurseries where they are hatched. Assiduous attention meantime is paid to the queen by other workers, who feed her diligently, with much self-denial stuffing her with morsel after morsel from their own jaws. A guard of honour in the shape of a few of the larger soldier-ants is also in attendance as a last and almost unnecessary precaution. In addition, finally, to the soldiers, workers, and queen, the royal chamber has also one other inmate the king. He is a very ordinary-looking insect (Fig. 9), about the same size as the soldiers, but the Fig. 5.-The Queen White Ant. Fig. 8. Eggs. arrangement of the parts of the head and body are widely different, and like the queen he is furnished with eyes. White Ant. Let me now attempt to show the way in which the work of the termites bears upon the natural agriculture and geology of the tropics. Looking at the question from the large point of view, the general fact to be noted is, that the soil of the tropics is in a state of perpetual motion. Instead of an upper crust, moistFig. 9 King ened to a paste by the autumn rains, and then baked hard as adamant in the sun; and an under soil, hermetically sealed from the air and light, and inaccessible to all the natural manures derived from the decomposition of organic matters these two layers being eternally fixed in their relation to one another-we have a slow and continued transference of the layers always taking place. Not only to cover their depredations, but to dispose of the earth excavated from the underground galleries, the termites are constantly transporting the deeper and exhausted soils to the surface. Thus there is, so to speak, a constant circulation of earth in the tropics, a ploughing and harrowing, not furrow by furrow and clod by clod, but pellet by pellet and grain by grain. Some idea of the extent to which the underlying earth of the tropical forests is thus brought to the surface will have been gathered from the facts already described; but no one who has not seen it with his own eyes can appreciate the gigantic magnitude of the process. Occasionally one sees a whole trunk or branch, and sometimes almost an entire tree, so swathed in red mud that the bark is almost completely concealed, the tree looking as if it had been taken out bodily and dipped in some crystallising solution. It is not only one tree here and there that exhibits the work of the white ant, but in many places the whole forest is so coloured with dull red tunnels and patches as to give a distinct tone to the landscapean effect which, at a little distance, reminds one of the abend-roth in a pine forest among the Alps. Some regions are naturally more favourable than others to the operations of the termites, and to those who have only seen them at work in India or in the lower districts of Africa, this statement may seem an exaggeration. But on one range of forest-clad hills on the great plateau between Lake Nyassa and Tanganyika I have walked for miles through trees, every one of which, without exception, was ramified, more or less, with tunnels. The elevation of this locality was about 5,000 feet above the sea, and the distance from the equator some 9°; but nowhere else have I seen a spot where the termites were so completely masters of the situation as here. If it is the case that in these, the most elevated regions of Central Africa, the termite colonies attain their maximum development, the fact is of much interest in connection with the geological and agricultural function which they seem to serve; for it is here precisely, before the rivers have gathered volume, that alluvium is most wanting; it is here that the tiny headwaters of these same rivers collect the earth for subsequent distribution over the distant plains and coasts; and though the white ant may itself have no power, in the first instance, of creating soil, as a denuding and transporting agent its ministry can scarcely be exaggerated. If this is its function in the economy of nature it is certainly clear that the insect to which this task is assigned is planted where, of all places, it can most effectively fulfil the end. The direct relation of the termites' work to denudation will still further appear, if we try to imagine the effect upon these accumulations of earth-pellets and grains of an ordinary rainy season. For two or three months in the tropics, though intermittently, the rains lash the forests and soils with a fury such as we, fortunately, have little idea of. And though the earth-works, and especially the larger ant-hills, have marvellous resisting properties, they are not invulnerable, and must ultimately succumb to denuding agents. The tunnels, being only required for a temporary purpose, are made substantial enough only to last the occasion. And in spite of the natural glue which cements the pellets of earth together, the structure, as a whole, after a little exposure, becomes extremely friable, and crumbles to pieces at a touch. When the earth-tubes crumble into dust in the summer season the débris is scattered over the country by the wind, and in this way tends to increase and refresh the soil. During the rains, again, it is washed into the rivulets and borne away to fertilise with new alluvium the distant valleys or carried downward to the ocean, where, along the coast line, it "sows the dust of continents to be." Herodotus, with equal poetic and scientific truth, describes Egypt as "the gift of the Nile." Possibly had he lived to-day he might have carried his vision farther back still, and referred some of it to the labours of the humble termites in the forest slopes about Victoria Nyanza. |