They have no horns, of course, but some have short antennÆ that stick out like little horns, and those we call shorthorned. The right name for the shorthorned grasshoppers is locusts. We call another insect a locust, but the shorthorned grasshoppers are the true locusts. Some say it was these locusts that John the Baptist ate with his honey in the wilderness. The Shortened Grasshoppers A good many people in different parts of the world still eat locusts. They are said to be good food when roasted, but I would rather eat roasted peanuts. Come here, little locust, and let us look at you. Now, stand still, and show us your short "horns." See its eyes! Yes, May, they are compound eyes, but I do not know how many facets they have. What a funny little rabbit face it has. See it move its little mouth parts. It bites bits out of the leaves and chews them up very fast. Has it teeth? May is asking. Well, yes, but not like our teeth. Sometime you must see the mouth parts of the grasshopper under the microscope. They are very interesting. Mollie says the locust has a cape on. John says the cape is the top of its thorax. Grasshopper Tribes Frank has been counting its legs; he says it has six. See it walk. It uses all six legs to walk with. But it does something besides walk with its hind legs. Yes, it jumps with them. How long and large they are! Now watch it jump. See! It draws those long hind legs close up to its body, then suddenly straightens them out—and away it goes as though it had been shot from a spring board. John says its hind legs work just like a spring, and so they do. It can leap several times the length of its body. Amy thinks it should be called a grass-jumper instead of a grasshopper. Suppose we all look carefully at the locust's long hind leg, segment by segment. What, John? You do not know what a segment is? Well, a segment is the part between two joints. The joints are where the leg bends, you know. May proposes that we draw a picture of the long hind leg. It will be fun to try. There are two tiny segments close to the body. If you are not careful, you will find only one. You must look sharp to see both of them. How well Charlie has drawn his! He has both the little segments. Grasshopper Tribes The one next the body we will mark I, and we will call it the coxa. The next little one we will mark II, and that we will call the trochanter. The long, strong one, III, we will call the femur. The next one, long and narrow, we will mark IV, and call the tibia. All the rest of the leg, made of several short segments, we will call the tarsus, and we will mark it V. Now how are we to remember all those hard names? Here is a jingle that perhaps will help us:— Coxa first, and then trochanter, Now let us see who can learn it first. Charlie says we are taking a good deal of trouble over the hind legs of a grasshopper. Grasshopper Tribes Very true, Mr. Philosopher, but let me tell you something. When we have learned the names of the segments in the grasshopper's hind leg, we have learned the names of the segments in the legs of all insects. You see all the legs are made on one common plan, and it is very convenient, as you will soon see, to have the parts named. What a fine set of drawings of the grasshopper's hind leg we have! Why do you suppose the coxa and trochanter are so small? Yes, John, it is in order that the leg can move easily. The grasshopper can turn its leg in almost any direction because of these small upper segments. It can put its leg up over its head if it wants to. Next to the little coxa and trochanter is the longest and largest segment in the grasshopper's leg; I suppose nobody remembers its name. Listen to little Nell,—"number three the femur stands." So it does, and what a very useful femur it is! If it were not for the long femur and the long, slender tibia, the grasshopper would not be a grasshopper—it could not hop at all. Watch the grasshopper, and see how he uses those long segments to jump with. Grasshopper Tribes First he draws the tibia close up to the femur—now he is off! He just straightened those long hind legs out with a jerk, and away he went! Grasshopper Tribes What do you suppose the two little sharp spines at the end of the tibia are for? What, May? You did not see any spines? Grasshopper Tribes Look again. See, Charlie has drawn them very plainly in his picture of the grasshopper's leg. Mark them s, Charlie. Now we must all look at Charlie's picture. He says he thinks he knows what the spines are for I have no doubt Charlie is right. May wants us to look at the beautiful little hinge x where the femur and the tibia are fastened together. Grasshopper Tribes Let us mark it X. See the little ball on the end of the tibia. How well it fits into the hollow on the end of the femur. In order to see this hollow or groove, you must look on the under side of the leg. Yes, John, it reminds us of the ball-and-socket joint, only this is a hinge joint, and does not move in so many directions. The tibia can move towards the femur and away from it on this hinge. When our little friend gets ready to jump, he draws the tibia close up to the femur. When he jumps, he pushes the femur quickly away from the tibia. If you watch the grasshoppers, you will soon understand just how they use their hind legs in jumping. The tarsus bends easily. It has three joints. The last segment is a cunning little foot. What is John doing? He is looking at the grasshopper's foot through the magnifying glass. Wise John! Let us all look. Yes, Charlie, we will try to draw it. Mollie has hers drawn already. Do not hurry too much, Mollie. You cannot draw well if you hurry. See the sharp claw on each side of the foot. Let us mark these claws a and b. Between them is a flat little pad which we may as well mark c. May says her picture looks like a crazy pond lily. Let us see, May. Well, it is rather funny. If I were you, I should try again. Any child can learn to draw who will keep trying. Touch the grasshopper's foot with the tip of your finger. How the little foot clings to you! It clings by the two little claws that have caught in your skin, and that hold fast. Grasshopper Tribes What do you suppose the little pad between the claws is for? It is important, I can tell you. John says he has heard there is a little pad in the fly's foot that enables it to walk on glass. Yes, and it is the same with the grasshopper. The little pad between the claws is fringed with hairs. You can see them with a good magnifying glass. Out of the tip of each hair comes a little drop of sticky liquid. This fastens the foot to any smooth surface. Many insects have these sticky hairs on their foot pads. When a fly walks up a window pane, it does it by gluing its feet, one after the other, to the glass. I don't wonder you laugh. No, Mollie, the glue does not harden and hold it fast. The fly can easily pull its foot loose. The grasshopper cannot walk on glass quite as well as the fly. Its foot pads do not cling so well. Grasshopper Tribes Would you not like to know the name of these curious little foot pads? We call the foot pad a pulvillus. Some insects do not have sticky hairs on the pulvillus. There are beetles that simply put the pulvillus so flat against a smooth surface that it stays there by the pressure of the air above. Some people think that is the way the pulvillus on the fly's foot acts. Perhaps it acts both ways, sucking fast and sticking by hairs. John wants to know if the beetle's pulvillus does not act just like the "sucker" that boys make. The sucker, you know, is a round piece of leather with a string attached to the middle. When the leather is wet and laid flat on the floor or on a smooth stone, all the air below it is pushed out, and the air above presses so hard that a boy cannot pull the leather up from the floor. Grasshopper Tribes You can peel it up from one edge and let the air under easily enough, and then a baby could lift it. When the insect wants to move, it peels its foot loose. It can do this very quickly. Mollie wants to know what all these little sharp spines on the back of the tibia are for. Let us look at them. There is a double row of them. Do they not look a little like a comb? I suspect that is what they are, the grasshopper's comb. Insects are very neat little folks. They are always cleaning their wings and their legs and their antennÆ and their bodies. The spines on their legs are very convenient for that. Charlie says he thinks the grasshopper's legs are as good as a whole box of tools. So they are, and you have not yet heard all they can do. The funniest is to come. Mr. Grasshopper sings his song with his hind legs! He rubs the inside of his femurs against the outside of his wings. There is a row of very fine spines down the inside of the femur for the use of the little fiddler. He scrapes away with these on his wing covers. Yes, Ned, his femur is his violin bow, and his wing cover is his violin. The noise he makes does not sound much like a violin, little Nell thinks. No, indeed, it does not. It is the shrilling sound we hear in the grass in the summer time. Grasshopper Tribes It is only the male grasshopper that sings. The little lady grasshopper sits still and listens to him. Now, let us look at the other legs. The front pair are the smallest. Can you find the little coxa and trochanter? Yes, Charlie, we will draw the little front leg. Let us number the segments as we did those of the hind leg. See, the femur is larger than the other segments, but it is small as compared to the femur of the hind leg. The tibia is shorter, too, than the tibia of the hind leg. The little tarsus is like the tarsus of the hind leg with its claws and its pulvillus, only, of course, it is smaller. The middle pair of legs is like the front pair, only larger. Now, see how the legs are placed on the grasshopper's body. Grasshopper Tribes The front pair are directed forward. When the insect walks, they pull. The middle and hind legs are directed backward. When the insect walks, they push. Well, little legs, you all have your own work to do, and you surely do it very well. Let me see, who has front legs as odd as the grasshopper's hind legs. Grasshopper Tribes Yes, Mollie, the mantis has. Let us look again at the mantis. Here is another picture of it. Its hind legs are just common walking legs, you see. And so are its middle legs. Grasshopper Tribes John says they are directed forward instead of backward. You can see why. They have to take the place of the front legs, that do not touch the ground at all. They have to hold Mr. Mantis up, and pull him along when he wants to walk. Now, let us see if we can make anything out of these front legs. The coxa is small and close to the body. The trochanter, II, is very large and long. Yes, Charlie, it increases the size and strength of the leg very greatly, by being thus enlarged. The femur, III, is large and strong, too, and it has a row of sharp, spiny teeth down the inside. The tibia, IV, is also well supplied with cruel teeth, and at the end of it is the tarsus, as you see. You know how the mantis uses these legs. The joint between the tibia and femur is a strong hinge joint. If can shut the tibia close to the femur, the spiny teeth of the one locking into the spiny teeth of the other, and forming a terrible trap for the insects that are so unfortunate as to get caught in its merciless grip. Altogether, you see, it is quite a terrible leg, though it has no more segments than a common leg. The segments are changed in shape and size from the regular leg segments. When any part is changed from the regular shape or size, we say it is modified. The front legs of the mantis are modified to catch and hold its prey. Yes, John, the hind legs of the grasshopper are modified too. They are modified to jump with. Ned says he didn't know there was so much to learn about a little thing like an insect's leg. Yes, indeed, there is a great deal to learn about all living things. I wonder how you would like to look at the grasshopper's wings for a little while. Here is one with large wings. Grasshopper Tribes See how they lie along each side of the body. They come together on top like the ridge of a sloping house roof. Yes, May, they are the roof to the grasshopper's body, and they help to protect it. Let us gently spread them out. Ah! these roof wings are not what the locust flies with at all. See, folded up under them is a pair of delicate gauzy wings. Grasshopper Tribes If we are careful, we can spread them out. We will use this dead grasshopper 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. Grasshopper Tribes How pretty the flying wings are when they are spread out! See, over there goes a grasshopper whose flying wings are bright yellow. And there goes another with red flying wings. Some of the grasshoppers are almost as pretty as butterflies when they are flying. They show their gay inner wings only during flight. As soon as the grasshopper comes to rest the inner wings close of themselves. The wing joints act like springs. The grasshopper does not have to think about shutting up its wings. Grasshopper Tribes 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 grasshopper. You see the grasshopper 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 grasshopper is pushed along through the air. As soon as it is done flying it stops moving the wings, and they instantly close of themselves. Grasshopper Tribes 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. Grasshopper Tribes What wonderful wings the grasshopper 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. Grasshopper Tribes Those larvÆ 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 grass. 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. Grasshopper Tribes It is easy to find these half-grown grasshoppers in the middle of the summer. Here is one that little Nell has caught. See its wing pads. Mollie says they are rudimentary wings. It continues to eat and grow and moult, and the little wings are moulted off with the rest of the skin—for the wings of the insect are only modified parts of the skin. But there are new and larger wings underneath, and these grow and are moulted off with the next skin, until, at last, the grasshopper is full-grown, with full-grown wings. Grasshopper Tribes It will not moult any more after that. When full-grown, the females lay their eggs. Where do you suppose they lay their eggs? Some of them make a hole in the ground. The end of the abdomen is very strong and sharp, and the locust can make a hole with it quite easily. When the hole is made, then the eggs are laid in it, and the locust covers the opening to the hole with a sticky substance to keep out the wet. The eggs usually lie in the ground all winter. Just think of the locust eggs there are under our feet as we cross the fields! Millions and millions of little eggs are hidden in the ground. Early in the next summer the little eggs hatch, and then tiny locusts creep up out of the earth and go hopping about everywhere. Most of the full-grown locusts die in the fall. As you know, the young ones have no wings, and this is why there are so few winged locusts early in the summer. Some locusts make their holes in fence rails or in old stumps. It is the locusts, or shorthorned grasshoppers, that sometimes come in swarms that darken the sun. There is nothing the Western farmer dreads so much as a swarm of locusts. I have heard how the grasshoppers came in Kansas one year. They appeared all of a sudden in countless millions. They were piled up against the fences clear to the top. They swarmed into the houses, and in places on the railroad track they were piled so deep the trains could not run through them. Think of a railway train being stopped by grasshoppers! They stripped every leaf from the trees and left them as bare as in winter. They ate up every blade of grass. But in the East they do not do so much damage, though they sometimes cause the farmers serious loss. When summer comes we may listen to their cheery din with pleasure. I am sure we shall enjoy the merry sounds of the grasshoppers all the more now that we know something about how they are made, and something about the little fellow that makes them. Grasshopper Tribes |