THE NATURALIST.

Otago Witness, Issue 1813, 20 August 1886, Page 33

THE NATURALIST.

LOWER INTELLIGENCE. INSECT MATHEMATICIANS. The spider, who, according to the timehonoured narrative, beguiled an unwary fly with a description of the aesthetic charms of his dining-room, was not, perhaps, after all, so much in advance of his race in the matter of intelligence as childhood's fancy may have pictured. The following instance of a similar and still more pressing invitation, though trifling in itself, seems to afford an evidence of reasoning power, the more marvellous the more closely it is examined. The spider in this case had constructed his large and elaborate web amongst the outer leaves of a Portugal laurel on the centre of a lawn. It was of the usual form, and so disposed as to offer, in his judgment, the [ best possible obstruction to the course of ! inward-bound insects on the wing. As he waited through the sunny hours, according I to his wont, his monumental patience at- | tracted the notice of a human observer sauntering round. While the observer watched, an impetuous fly flung himself headlong at the web with such vigour that, although it detained him for one second, the force of his flight carried him clean through it, and he alighted on a leaf several inches from its inner side, towards the interior of the bush. The spider made a spring during the fly's momentary contact with the web, but was too late. It was, however, soon apparent that he had not lost sight of him, and had resolved not to give it up as a hopeless case ; though the fly sat on an isolated leaf clear away from the web. The spider returned, and the observer noted that he now placed himself, not on his customary throne in the centre of the web, but at a particular point somewhat above it, and nearly • half-way between it and the upper edge. Here he sat for some minutes without any sign of stirring ; the fly on his leaf below also remaining perfectlymotionless. It must be mentioned that the hollow space among the leaves, within which the fly sat, was all but completely fenced in by the web ; there was, in fact, but one small clearance through which he could make a direct escape, unless he chose to risk another dash through the web itself. At last the move came ; so instantaneously that its effect loses something even by being put into words. The fly made a straight rush for the opening. At the same instant the spider dropped from his perch like a stone, clasped the body of the fly in mid-air, and the combined, momentum of the sidelong flight and the downward drop swung both of them back against the meshes of the web, where in another half-minute the unhappy fly had been dealt with after the usual fashion. Now the calculations, of the spider inde-

1 termining the exact spot from which the exploit could be effected must have been made with a nicety and precision not lesg than amazing. Had he miscalculated the time or force of the flight, or timed his own drop the hundredth part of a second out, he must either have missed altogether, or have landed somewhere down in the leaves, where the fly, not hampered by the meshes of the web, would almost surely have made good his escape. One of the earliest lessons of the student in natural philosophy teaches him that what is called the "resultant " of any two forces meeting from different directions takes a line dividing the angle between them in a proportion related to the forces themselves. This line the spider had to reckon, in order to make sure of landing himself and his quarry at the only spot where he could hope to secure it. The force of the flight, its exact probable direction, the momentum of his own body, the line of his fall, the time occupied by each, the position of the web, and its angle ; all these mathematical conditions must have been perceived wi^i unerring accuracy^ by the astonishing instinct which led the spider to the one and only spot from which the thing could possibly be done ! What say our Senior Wranglers to this I bit of brain work ? A SUBTERRANEAN FIEND. As a shining light of four-footed intelligence, most persons would hesitate to name our old rustic acquaintance the Pig. An Irishman might, perhaps, be found who would regard him as a quadruped of " light and leading," but only in some inverted sense wTiich will not bear investigation. As a rule, the phrase "pig-headed" points to a character which not only cannot lead, but is not susceptible of being lod. " I won't be druv," is a county motto, said to apply especially to the natives of one of our southern shires ; and it is scarcely possible to refer its origin to any but one parallel. The pig is probably an animal more or less maligned and misunderstood, perhaps nearly as much so as his human superiors habitually malign and misunderstand each other. But though his brain may be lacking in quantity, it is difficult to deny that whats he does possess is sometimes " all there," as witness the following fact. The pig owns a variety of cousins, of a non-domestic habit, in various parts of the world. One of these inhabits the forest or scrub-lands, extending over a vast region of North- West Africa, especially near the coast; line. It is there that a singular and highly interesting superstition prevails amongst the Mohammedan population as regards the hereditary affinity of the wild boajt for vagrant evil spirits. The current belief is that every one of them is tenanted by a spiritual ne'er-do-well from the community whose " name is Legion," and for this reason the animal himself is regarded with devout awe; especially at any time after four o'clock in the afternoon, at which hour the bond of union between piggy and his " familiar " is believed to be relaxed until the following sunrise, So deep a hold has this peculiar tradition on the popular mind that it is not unusual in Moorish country houses to see a young wild pig penned up in the corner of the stable, the purpose being that he may act as an " absorbent of any stray demoniac influence that might be loafing round, to the detriment of the horse or mules. Excepting for some such praiseworthy object as this, the sons of Islam would rather handle a scorpion than the malevolent porker. In one such farmstead, where the above safeguard was studiously preserved, the protective pig was the hero of an intensely comical incident. Weary of his confinement, the squeaker amused himeell at frequent intervals with his natural predilection for earth-grubbing, which he carried on in his own corner until, at last, he had succeeded in worrying out a hole big enough to hold him two or three times over. At the bottom of this hole he one evening fell placidly asleep, and the attendant labourer coming round in the dusk and not perceiving the pig, came to the conclusion that he had made his escape. With native nonchlance he at once accepted the inevitable, and proceeded to make things tidy (pending the capture of a new pig) by kicking away the rough partition and shooting a big barrow-load of loose mould into the hole. He then left the stable ; while piggy, out of his peaceful slumbers, came gradually to a sense that he was buried alive ! A very few minutes sufficed to scramble his way out again, and take a look round. The firsfc thing he noted was that, in availing himself of the increased space, the farmer had put down, close to the corner, a large bundle of mixed grass and roots destined for fodder for the mules. Now, fiiggy knew by experience that this heap of odder (which comprised sundry pickings congenial to his own appetite) was' always to be found in the stable, but had hitherto been kept provokingly out of his own reach ; " and therefore," he argued to himself, " if I can manage to continue my sojourn here without attracting further attention, I shall always be sure of an easy meal, whereas I may go farther and fare worse outside." Acting on this design, he at once proceeded to make a substantial supper, after which, hearing the approach of the farmer, he returned to his hole, and once more scuffled himself into the loose mould with such success as to leave only his snout above ground, for breathing purposes. Of course, he was not observed, and this innocent device worked excellently for several days; when, one unlucky morning, the labourer, casting his eye round upon the loose mould in the hole, suddenly bethougt himself of adding to the general tidiness of things by jumping in and treading it down,with a view to fill up with some more, and he jumped and trod accordingly. The awful result may, perhaps, be left to reader's lively imagination. He will at least forgive the poor Moor if he fled like a hunted hare to his master, and swore by Allah that the Shaitan himself had come up from the nether world by a private paseaae through the stable J ,