If we are careful, we can spread them out.
We will use this dead gra.s.shopper that Charlie has found.
What pretty wings! So dainty! And how cleverly they are folded up, like little fans.
Who would imagine such delicate gauzy wings were folded away under the hard, stiff roof wings.
The roof wings are called wing covers, because they cover up these pretty inner wings.
The locust does not fly with the wing covers.
It spreads them out wide to get them out of the way.
It flies with the inner wings.
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How pretty the flying wings are when they are spread out!
See, over there goes a gra.s.shopper whose flying wings are bright yellow.
And there goes another with red flying wings.
Some of the gra.s.shoppers are almost as pretty as b.u.t.terflies when they are flying.
They show their gay inner wings only during flight.
As soon as the gra.s.shopper comes to rest the inner wings close of themselves.
The wing joints act like springs.
The gra.s.shopper does not have to think about shutting up its wings.
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John says it has a spring in its wing covers too.
Open the wing cover.
There, it locks itself, as it were, and stays open without any effort on the part of the gra.s.shopper.
You see the gra.s.shopper wants its wing covers to stay open and out of the way of the inner wings when it flies.
So it just opens them, and there they are.
It moves the inner wings very fast indeed when it is flying. It would not do at all for them to be fastened open.
If it did not move them, it could not fly. The wings fairly _whirr_, they go so fast. They beat against the air, and thus the gra.s.shopper is pushed along through the air.
As soon as it is done flying it stops moving the wings, and they instantly close of themselves.
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Then it unlocks the wing covers and they shut down over the inner wings.
They shut down very tightly. They overlap, as you can see, just below where they are fastened to the insect"s body. Thus they form a very good roof.
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What wonderful wings the gra.s.shopper has!
And there is something more to be said about them.
Some species of locusts use their wings as musical instruments. When they wish to, they rub the upper end of the inner wings against the upper end of the wing covers when they are flying.
This makes the crackling sound we sometimes hear when the locusts fly.
What is that, Mollie? You have caught a locust that has no wings at all?
Who can guess why?
Ah, yes, our wise John says he thinks it is because it is a young one.
What makes you think so, John?
I know, you remembered the larva of the dragon fly and of the May fly.
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Those larvae had no wings at first, but the wings grew, and finally at the last moult they were full-sized.
When first hatched, the locust larva is like the full-grown locust, only, of course, it is very small, and it has no wings at all.
It is a little dot of a thing with an enormous head.
Here are three clinging to a blade of gra.s.s.
Are they not funny little rascals!
The baby locust eats and grows and moults until, finally, the wings begin to show as little pads at its sides.
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It is easy to find these half-grown gra.s.shoppers in the middle of the summer.
Here is one that little Nell has caught.
See its wing pads.