OUR PUBLIC SCHOOLS COLUMN.

Otago Daily Times, Issue 13637, 5 July 1906, Page 2

OUR PUBLIC SCHOOLS COLUMN.

FOR BOYS AND GIRLS [Conducted by Maoister, to whom all commußicalions imist be addressed.] PROTECTIVE RESEMBLANCE IN" NEW ZEALAND -MOTHS. Some time ago I gave an article on moths and huttcrifies, taken from (lie Victorian Education CaK-ite. and .Mr Howes was subsequently kind enough to contributean article more valuable to us because it dealt with New Zealand moths and butterflies and corrected any false impressions which might, liavo been caused by the previous article. At the last me-.'ling of the Otago Institute a paper was-contributed by ilr Philpotls, ii Southland enthusiast, lmt', unfortunately tor my leaders, it has gone to Wellington, so I cannot outljno it. Dr Bcnham, however, at my request courteously placed at, my disposal not only his notes on the kca, but his notes on Mr I'hilpoUs's paper also. In effect they read something like the following:— • • The colours of animals are not- merely of aesthetic interest to us as human beings but also to the animals themselves. They arc, in various wfiys, of the utmost protective value in the struggle for existence. The bright contrasted colours of some seem to advertise the fact that lh?y are possessed of some noxious property—a sting, a nasty taste, for instance—and enemies arc thus duly warned to leave them alone. Others—and theso are more numerous—harmonise with their surroundings: the closer the harmony tho greater the, protection. These facts are well illustrated % insects, moths, and butterflies.

■Some moths resemble the bark of trees; flllicrg fallen leaves, in various stages of decay; others, lichens, etc.: and in each ease the naturalist, finds it difficult to detect them. It miist not ho imagined, however, that, tho moths, etc., are conscioi's that they « r o hiding themselves. ]!y a. long proeefs of selection tlio more conspicuous have 'been weeded out, leaving only Ihnso highly ii'roteeiod. Hut. moths are very variable—i.e., from a single lot of eggs iho individuals, within certain limits, vary in their tints and .narkings. Now, if we cxa'mino a lot of decaying leaves, it is seen that they, too. present all tones of brown and yeliow— that a single leaf is variegated, is splashed with lighter or darker tints—perhaps covered with a black or a. white funcus, so a moth or a butterfly which, in a. cabinet, appears .conspicuous, becomes, in its natural surroundings, difficult of detection.

It is advisable, if possible, to set moths and butterflies in collections, in natural surroundings, and as they are when at rest. Sonic settle with open wings, others with fore-wings covering the bind ones; some have the wings more or less closed above the back, others, may be, roll the wings. Some, again, when pursued will fall with open wings and look like leaves. These harmonics arc brought about by Natural selections—i.e., those Varieties which hnnroniso most, will avoid detection and so survive. Again,' as natural selectioh leads I to the survival of tho fittest in the hunted. I it leads to tlio fame in the hunter, for those having tbi» l keenest sight or flcent or hearing naturally liave a greater amount of food and a bettor chance of surviving and reproducing themselves. The keener vision, etc., again, brings about more perfect harmony still. In bis remarks, Dr. Benham says that when in tho Taxman Valley lie plucked a yellow flower, inul only when carrying : it .".way did he notice upon it a butterfly with dosed wings, of a bright yellow colour. MIMICRY IN NATURE. • This means the same as Protective Resemblance, but I malic a fresh heading to introduce a i; notation from Wallace's "Malay Ardiipckitjo," published in Macmiilan's Colonial Library. In referring to the butterfly named Kallima pnralokta, bo says;— . "Its upper surface is of a rich purple, variously tinted with ash colour, and across the forcwings thorn is a broad bar of deep orange, so that when on tho wing it is very conspicuous. .. . I often endeavoured to capture, it. without success, for after flying a short distance it would enter a. bush among dry or dead leaves, and however carefully 1 crept up ic the spot I could never discover it till it would suddenly start out again and then disappear in a similar place. At length I was fortunate to see (he exact spot where the butterfly settled, and though I lost sight of it for some time I at length discovered that it was close under my eyes, lint that in its position of repose 1 it so closely resembled a dead leaf attached to a twig as almost certainly to deceive the eye even when gazing fully upon it, I captured several specimens on the wing, and was fully abln In understand the way in which this wonderful resemblance is produced. "The ends of the upper wings terminate in a finu point, just as the leaves of many tropical shrubs and trees aro pointed, while the lower-wings are somewhat morn obtuse and aro lengthened out into a. short, thicktail. Between these two points there runs a dark curved line, exactly resembling tho midrib of a leaf, anil from this radiate on each side a few 'oblique marks, which well imitate the lateral veins. These marks are more clearly scon on the outer portion of the base of .the wings, and on the inner side towards the middle and apex, and they are produced by stria?, and markings, which aro very common in allied species, but which am here modified and strengthened so as to imitate moro exaotly the venation of a leaf. The tint of the undnrsurface varies niuch, but it is always some ashy brown' or reddish colour, which matohes with that of dead leaves. The habit of the species is always to rest; on a twig and among dead or dried leaves, and in this position, with tho wings closely pressed together, tho butterfly's outline is exactly that of a moderately-sized leaf, slightly curved or shrivelled. The tail of the hind wings forms a perfect stalk, and touches the stick while the insect is supported by the middle p'air of legs, which are not noticed among the twigs and fibres surrounding it. The head and antenna; are drawn back between the wings, so as to be quite concealed, and there is a little notch hollowed out at the very base of tho wings, which allows the bead to be retracted sufficiently. All these varied details combine to produce n disguise that is so complete and marvellous as In astonish everyone who observes it, and the habits of tho insects are such as to utilise all these, peculiarities and render them available in such a manner as to reniovo all doubt as to the purpose of this singular case of mimicry, which is undoubtedly a protection to the insect. Its strong and swift flight is sufficient to save it from its enemies when on tho wing, but if it were equally conspicuous when at. rest it would not long escape extinction, owing to attack of the insectivorous birds and reptiles that abound ill tropical forests. A very closely allied species, Kallima jnachis, inhabits India. . . .' On examining a number of these it will bo seen that no two are alike, but all .the varieties correspond to those of dead leaves. Every tint of yellow, ash, brown, and red is found here, and in many specimens there occur patches and spots formed of little black dots, so closely resembling the way in which minute fungi grow on leaves that it is almost impossible at. first noi. to believe that fungi have grown on jho butterflies themselves. "If such an extraordinary adaptation as lliisstoodalone.it would be very difficult to oiler any explanation of it; but though, perhaps, it is the most perfect case of protective imitation known, there are hundreds of similar resemblances in Nature, and from these it is possible to deduce a gonoral theory of 'the manner in which they have been sjowly brought about. The principle of variation and that of ' natural selection/ or survival of the fittest, as elabor-

atod by Mr Darwin in his ' Origin of Speoies.' offers Iho foundation for such a theory." Next week, nil being well, I'll give oilier illustration* of mimicry in Nature, this time culled from Druinmond's "Tropical Africa." Perhans some readers can forward specimens or give particulars of mimicry in Nature in New Zealand. CLIMATOLOGICAL ABSTRACT. Last week 1 promised tin's observational abstract. Dr Giinn suggests that local winds be divided into eight points; Tim cloud scheme I am not giving because I think ii will be impossible to tabulate results for this column. The rest may bo managed, but I am afraid of it. To stvo space, only January to .liilv are inserted:— ABSTRACT OF CUMATOLOGICAL OBSERVATIONS. For year 100 , As made a 1; ICaikoura, Marlborough, Xew Zealand, at !> a.m.; situated 10 miles south of Kaikoura Ranges, the altitude of which is 8000 ft. Latitude, 42° \>6' 30" S.; height above sea level, 50ft; longitude, 173° 45' E.; distance from sea, onc-qunrter of a mile, John St. C. Obns, M.8.C.M.. FJi.Jlet.S., Observer.

TEMPEKATUliE. _ RAINFALL. s LOCAL WIND. _ S ___ , , . n ,.•„„ Amount Mean of 5= . O Ktlatiye Previous n 2 Mians. Extremes. Greats'. Days Humidity q. jU1 j Yeais. 2 - ' ~~~ one day. kmd. - , 9 a.m. Mca . May. Miu. Ranse. Highest. Lowest. _ o o o~~ o o o o Iiidiss. Incaes. Percent. 0-10. Jan. Feb. . ' . April M"y ,