A couple of boys were once climbing about some disused scaffolding in a lonely place, when a beam on which they were standing gave way under their feet. Both fell, the elder a little before the younger. But just in time the elder managed to clutch another beam and hold fast to it. By a providential coincidence, his brother, catching wildly at anything within his reach, seized his legs, and the two hung suspended thus, with all the weight on the elder boy's arms. Before long, the strain became too great, and he called out to the other that they were lost, for he could hold on no longer. No one was near, and there was little hope that their cries would attract attention.
'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 butterfly 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 butterfly 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 horny cases or shields for the protection of the hinder wings, which lie beneath them when not in use.