XI.—CATERPILLARS AND THEIR ENEMIES.
The caterpillar of the North American Great Peacock moth (fig. [4]) is armed with numerous tufts of prickles ending in minute black points which pierce the hand if touched, and cause severe pain. These spines, as shown in the illustration (fig. [2], a b, on page [357]) are hollow, and filled with liquid poison. 'a' is the portion which breaks off; 'b' the hollow base which contains the poison.
In some few caterpillars the poison spines take the form of balls armed with short prickles and one large spike; hence they are known as caltrop spines (fig. [2], c), from their likeness to the cruel weapons, known as caltrops, which used to be scattered over the ground in time of war to repel the attacks of cavalry; the spikes forced their way into the horses' feet when trampled on, and so disabled them.
The spines of the caterpillar of our Oak Eggar moth are very brittle, and in handling these insects, great care must be taken, as cases are known of blindness having been caused by the spines being carried into the eyes by the fingers.
Let us now turn to the liquid squirts with which some caterpillars are provided. Our Spurge-hawk caterpillar, for example, when threatened, squirts from the mouth a spray of poison. In our illustration (fig. [5]) it is shown repelling the attack of the dreaded ichneumon fly by means of this spray. The quaint Puss moth, which many Chatterbox readers must have seen, can squirt out an irritant fluid, generally supposed to be formic acid, from the mouth, when alarmed, and this, if it enters the eye, causes acute pain.
Fig. 4.—North American Great Peacock.
The caterpillars of the Swallow-tailed moths, when irritated, give out an offensive smell, but they are unable to 'spray.'
Many beetles have the power of forcing drops of blood from a minute hole in one of the legs. This blood is saturated either with a fluid which causes a burning sensation on everything it touches, or with an intolerable odour; in either case the result is the same—they are given a wide berth by all who have discovered their power. The little lady-bird beetle, for example, sends out, when frightened, a tiny drop of a yellow fluid from the 'knee-joint,' which has a smell like opium. The Javanese 'violin-beetle' gives off a fluid which is said to paralyse the fingers for twenty-four hours.
Fig. 5.—Caterpillar of Spurge-hawk Moth fighting Ichneumon Fly.
W. P. Pycraft, F.Z.S., A.L.S.
THE BLACK SWAN.
The Black Swan is an Australian bird, and was not known in Europe until that continent began to be explored, although black swans had been often spoken of before that time as a kind of fabulous monster. The ordinary white, or mute, swan, which graces our rivers and lakes, has been admired, and even protected by laws, for many centuries, and its plumage is so beautifully and uniformly snowy that we can hardly be surprised if people thought that all swans must be white, and should regard a black swan as impossible, like the two-necked swan sometimes painted upon inn-signs. But travellers have discovered many strange animals in unexplored countries, and we now know that there are not only black swans, but even swans that have a black neck and a white body.
The plumage of the black swan, with the exception of the quill feathers, which are white, is entirely black. The bill and the skin between the eyes are a beautiful red, which contrasts handsomely with the black feathers. The tail of the bird is very short, and, next to the colour of the plumage, this is the chief peculiarity which distinguishes it from the white swan.
The black swan frequents the swamps and secluded bays on the Australian coast. It is not a very shy bird, and is frequently seen by the sportsman and the camper-out. It enjoys the companionship of its kind, and congregates usually in small flocks. August and September are, it is believed, the breeding months, and shortly before this the swans leave the swamps and seek the nesting-grounds, which are usually on the islands in the bays. Western Port Bay, not far from Melbourne, is one of their favourite haunts. The nest is a collection of reeds, and in this the female swan lays five or six eggs of a whitish-grey colour, and a little smaller than those of our white swan.
The black swan is rather strong upon the wing, and, when flying, it frequently utters a musical cry. But, being a heavy bird, its flight is very exhausting, and it appears to have more confidence in its webbed feet than its wings. It is said that when it is startled it tries to escape by swimming, if it can, rather than by taking flight. As the birds breed upon islands on the coast, they may occasionally swim out, or be drifted out, to sea. A short time ago, two black swans were picked up off Norfolk Island. They were miles away from the nearest part of Australia, and they must have been driven from their native land by winds and currents until they were lost. They were greatly exhausted when taken up, but a bath in fresh water and a good supply of food soon put them right again.
This incident is not only interesting because it shows the endurance of the swans and how long a journey they may sometimes make almost by accident, but because it illustrates the way in which animals which are natives of one country may be carried to a new one. If these two swans could have continued on to Norfolk Island, which is about nine hundred miles from Australia, and, after arriving there, could have recovered their health, made a nest, and reared a brood of young ones, then there might have been black swans in Norfolk Island as well as in Australia. These swans were probably too much exhausted to have accomplished this long journey, but we have many reasons for believing that animals have often been unwillingly driven by winds and currents to new homes across the seas, and have thus helped to extend their species over a larger portion of the earth.
W. A. Atkinson.
AFLOAT ON THE DOGGER BANK.
A Story of Adventure on the North Sea and in China.