'Could you save yourself if I let go?' asked the younger.

'I think so.'

'Then good-bye, and Heaven bless you,' said the little boy.

With these words he let go, and was dashed to pieces upon the ground beneath. His brother, thus released from the additional weight, was able to pull himself up to a place of safety.

INSECT WAYS AND MEANS.

V.--HOW INSECTS FLY.

The wings of insects are like those of bats and birds only in the work they do. In another respect they are quite different organs. The wings of the bird and the bat, for instance, are formed from the front pair of limbs, but the wings of insects are formed on a very different plan from the walking limbs, of which there are never less than three pairs. The bat and the bird have only one pair of wings, the insects have two, though in many cases the hinder or second pair have been reduced to the merest stumps, or vestiges, as they are called. In other words, they are all that is left of a once useful pair.

The b.u.t.terfly has two pairs of wings; the fly is a good example of an insect which has but one pair. The stumps or vestiges of the second pair can only be found after careful search. But these vestiges--which are known as the 'balancers'--have a new use, and probably act as organs of hearing as well as to guide the flight. The b.u.t.terfly uses both pairs of wings in flight, the beetle only the hinder pair, the pair that in the fly are only 'vestiges.' The front pair of wings in the beetle form hard h.o.r.n.y cases or shields for the protection of the hinder wings, which lie beneath them when not in use.

The wings of insects are often brilliantly coloured, and this colour may be caused in two very different ways. Generally the colours of the wings are due to the way the surface of the wing is made, for this surface reflects light. But the colour of the wing of the b.u.t.terfly is to be traced to a quite different cause. If the fingers be rubbed over the surface of a b.u.t.terfly's wing, they will be found to be covered with a fine coloured dust, whilst the wing itself will become quite transparent (as in fig. 1). If this dust be looked at under the microscope, it will be seen that it is made up of a number of tiny scales, most beautifully shaped (as in fig. 2). Each scale is fixed to the surface of the wing by a tiny stalk and in a regular order.

From the shape of the wings in the b.u.t.terfly or moth we can tell more or less how the insect flies. Long and narrow wings give a swift and rapid flight, broad round wings a slow and leisured flight.

The wings of insects are moved by only a few muscles, but with wonderful rapidity. It has been calculated that the common fly makes with its wings three hundred strokes per second, the bee one hundred and ninety.

The dragon-fly and the common cabbage-white b.u.t.terfly of our gardens, however, have a much slower beat of their wings, the former twenty-eight strokes per second, the latter only nine. The machinery by which they move is like that of an oar.

[Ill.u.s.tration:

1. b.u.t.terfly's Wing (magnified).

2. Scales from b.u.t.terfly's Wing (greatly magnified).

3. Earwig (magnified): one wing folded, the other open.

4. Foot of Fly (greatly magnified).]

Insects' wings are folded in various ways. Those of the b.u.t.terfly, when at rest, are raised up over the back, so that the upper surfaces of the right and left wings come together. In the moth the hinder wings pa.s.s under the fore-wings, which are held flat over the back. But the beetle and the earwig hide their hind-wings beneath a hard case not used in flight. The size of the hind-wings, however, is so great that before they can be covered by the h.o.r.n.y case, they have to be folded up, and this is done in a really wonderful manner, especially by the common earwig.

Most people probably think of the earwig as flightless; but, nevertheless, beneath a tiny pair of h.o.r.n.y wing-cases, a very wonderful pair of transparent wings is cunningly tucked away. The marvellous way in which they are folded up after use we cannot describe in detail here. In each wing there is a hinge shaped somewhat like a half-moon, in the middle of the stiff front edge (fig. 3, in the wing extended on the left). When the hinge is bent, the outer half of the wing folds over towards the tail, and the tip points forward. The further inward folding of the hinge of this rod next appears to divide the wing into two, the second portion pa.s.sing under the first, and thus bringing the wing down to half its original size. By this time the mechanical or automatic folding process stops, and the rest of the folding up has to be done by the aid of the pincers at the end of the body. Finally the packing up is complete, and the two hard outer cases, like a couple of tarpaulins, are drawn over the delicate wings to protect them.

On the right side of the body, in fig. 3, the wing has been folded up, and is covered by the wing-case.

The folding of the beetle's wing is also done by means of a hinge, but the packing up is less close, as the outer covering cases are larger.

Most insects walk as well as fly, and their walking is not less wonderful than their flight. Fig. 4 represents the foot of a fly. It will be seen, under a strong microscope, to have a pair of large claws and a pair of leaf-like plates, one on each side. The claws and the plates have different uses. The plates are used when the fly is walking, say, up a window-pane or along a ceiling. They are moved so as to lie flat on the surface which the fly is crossing, and when they are laid flat a number of tiny hairs are pushed out from them, from the tips of which a sticky liquid oozes, so that the fly is practically glued to the surface on which it is crawling. The claws are used to cling on to uneven surfaces, on which they can get a good grip. In the next article we shall say more about the way in which insects walk.

W. P. PYCRAFT, F.Z.S., A.L.S.

[Ill.u.s.tration: "There stood Captain Knowlton."]

THE BOY TRAMP.

(_Continued from page 175._)

During the meal Mr. Westlake talked about cricket, asking whether I played, and I explained that there had not been enough of us at Castlemore to make a proper eleven. He inquired further about Mr. Turton and Mr. Windlesham, and gradually led the conversation round to the days when I used to live in Acacia Road with Aunt Marion. I told him that she had married Major Ruston, and gone to India, but that I did not know her address nor Major Ruston's regiment.

'We can soon find that out,' he said, and sent the butler for the _Army List_. When he had looked in this, he raised his eyes to my face again, mentioning the number of the regiment, and explaining that it was at present at Madras.

Then he turned to the book again. 'I don't find Captain Knowlton--didn't you say that was the name?' he asked.

'Yes,' I answered, 'but he left the service when he came home from India, four or five years ago. He came into a lot of money, you see.'

'And Captain Knowlton was your guardian?' he asked, fixing his eyegla.s.s.

'Not exactly an ordinary guardian,' I explained. 'My father was a soldier too, and Captain Knowlton said he saved his life, and that was why he looked after me.'

After I had told him all about Mr. Parsons, he rose and went to the room where I had first seen him, calling me to follow. I shut the door when Mrs. Westlake had entered, and Mr. Westlake stood lighting a cigar.

'Upon my word,' he said, in his slightly drawling voice, 'there seems to be only one thing that is possible to be done with you for the present, Everard.'

'What is that?' I asked, with considerable misgiving.

'Naturally,' he continued, 'I shall write to Major Ruston and explain the exact circ.u.mstances in which Mrs. Westlake found you, and I have no doubt that when he hears what I shall tell him, he will make some sort of arrangement for your future.'

'But it will take a long time to get an answer.'

'No doubt, but you seem to be placed in a very awkward position. As far as I can understand, Captain Knowlton had every intention of looking after you if he had lived----'

'Oh, yes!' I cried, 'because he told me I was to go to Sandhurst.'

'But, you see,' he said, 'he did not make a will. Is that right?'

'Yes,' I answered. 'Mr. Turton found out the address of his solicitor, and told me there was no will.'

'So that, except your aunt in India,' he continued, 'there appears to be no one upon whom you have the least claim. Yet, Mr. Turton----'

'I don't want to go back to Mr. Turton,' I cried, taking a step towards him.

He took his cigar from his lips, and stood gazing for a few seconds at the ash, which he then knocked off into the fender.

'That is all very well,' he said. 'I suppose no boy who ran away from school ever felt any strong desire to return. But I understand that you admit that Mr. Turton tried to find you--that, in fact, he would have found you if Jacintha had acted as she ought to have done.'

'I don't want to get Jacintha into a row,' I exclaimed, and the slightest of smiles lighted his face.

'I am certain you don't,' he answered, 'and you need not trouble yourself on that score. But as Mr. Turton tried to find you, it is pretty clear that he wished to take you back with him. Now, if he wished to take you back, he could not have had any strong objection to keeping you. You don't complain that he treated you brutally?'