"Oh, I see! It is catching, isn't it? I have seen some bad cases, especially in small towns. Every young lady, even just girls"—I glance sidewise at Mary—"down with it. But is that what those boys over there are doing? I hope they won't interfere with the tarantulas. They probably don't know what lively times there are at nights in that field. Scores of big black tarantulas racing about, hunting, and hundreds of beetles and things racing about, trying to keep from being eaten. Well, I'd better begin, because we have to get back by luncheon time. I have a most profound lecture to give on Orthogenesis and Heterogenesis to that unfortunate Evolution class at two o'clock."

"I'm all ready," said Mary, looking up at me with confidence. She appreciates the kind of lectures I give outdoors, even if the lunch-gorged students don't appreciate my efforts ex cathedra.

"Well this summer invasion that I promised to tell you about happened when I was a boy in a little town in Kansas. It was in Centennial year; the one-hundredth anniversary of the freedom of the United States, and the summer of the Centennial Exposition at Philadelphia.

"I was going down town one day in July to buy some meat for dinner. I was going because my mother had sent me. Naturally this promised to be a very uninteresting excursion. But you never can tell.

"When I had got fairly down to Commercial Street, I saw that all the people were greatly excited. Some were talking loudly, but most were staring up toward the sun, shading their eyes with their hands. Then I heard old Mr. Beasley say: 'That's surely them all right; doggon, they'll eat us up.'

"My heart jumped. Who could be coming from the sun to eat us up? I burst into excited questions. 'Who are coming, Mr. Beasley? I can't see anybody.'

"'Hoppers is coming boy; see that sort o' shiny thin cloud up there jest off the edge o' the sun? Well, them's hoppers.'

"'But how'll they eat us up, Mr. Beasley? No grasshopper can eat me up.'

"'They'll eat us up with their doggoned terbaccy-spittin' mouths; thet's how. And they'll eat you up by eatin' everything you want to eat; thet's how, too. Havin' nothin' to eat is jest about the same as bein' et, accordin' to the way I looks at things.'

"It is evident that Mr. Beasley was a philosopher and a pessimist; that is, a man who sees the disagreeable sides of things, who doesn't see the silvery lining to the dark clouds. In fact, in this particular case Mr. Beasley was seeing a very dark lining to that silvery cloud 'jest off the edge o' the sun.'

"I stared at the thin shining cloud for a long time, wondering if it were really true that it was grasshoppers. People said the silvery shimmer was made by the reflection of the sunlight from the gauzy wings of the hosts of flying insects. It occurred to me that if the hoppers were just off the edge of the sun, they would all be burned up, or at least have their wings so scorched that they would fall to the ground. However, as the sun is 90,000,000 miles away from the earth, it would take a very long time for the scorched grasshoppers to fall all the way. I guessed that we might have a rain of dead and crippled hoppers about Christmas-time. Anyway there were no grasshoppers now, dead or alive, in the street. And I decided, rather disappointedly, that we probably shouldn't get to see any of the live hoppers at all. Then I asked Mr. Beasley where they came from.

"'Rocky Mountains,' he answered, shortly.

"This seemed a bit steep, for the nearest of the Rocky Mountains are nearly a thousand miles west of Kansas. And to think of grasshoppers flying a thousand miles! A bit too much, that was. Still I thought I ought to go home and tell the folks. But mother interrupted me in my picturesque tale with a dry request for the meat. Oh, yes. Oh—well, I had forgotten. So the first disagreeable result for me from the grasshopper invasion of Kansas in the summer of 1876 was a painful domestic incident.

"But Mr. Beasley was right. The grasshoppers had come. Next morning all the boys were out, each with a folded newspaper for flapper and a cigar-box with lid tacked on and a small hole just large enough to push a hopper through cut in one end. The rumor was we were to be paid five cents for every hundred hoppers, dead or alive, that we brought in. As a matter of fact nobody paid us, but we worked hard for nearly half a day; that is as long as it was fun and novelty. By noon the grasshoppers were an old story to us. And besides there were too many of them. Hundreds, thousands, millions,—oh, billions and trillions I suppose. And all eating, eating, eating!

"First all the softer fresher green things. The vegetables in the little backyard gardens; the sweet corn and green peas and tomato-and potato-vines. Then the flowers and the grasses of the front yards. Then the leaves of the dooryard trees. Then the fresh green twigs of the trees! Then the bark on the younger branches!!

"And you could hear them eat! Nipping and crunching, tearing and chewing. It got to be terrible, and everybody so downcast and gloomy. And the most awful stories of what was going on out in the great corn-fields and meadows and pastures. Ruin, ruin, ruin was what the hoppers were mumbling as they chewed.

"And then the reports from the other states in the great Mississippi Valley corn-belt came in by telegraph and letter. Over thousands and thousands of square miles of the great granary of the land were spread the hordes of hoppers. Farmers and stockmen were being ruined. Then the storekeepers and bankers that sell things and lend money to the farmers. Then the lawyers and doctors that depend on the farmers' troubles to earn a living. Then the millers and stock-brokers and capitalists of the great cities that make their fortunes out of handling and buying and selling the grain the farmers send in long trains to the centers of population. Everybody, the whole country, was aghast and appalled at the havoc of the hopper.

"What to do? How long will they keep up this devastation? Have they come to settle and stay in Kansas and Nebraska and Iowa? What will the country do in the future for corn and wheat and pigs and fat cattle?

"Well, it would be too long a story to tell of how all the entomologists went to work studying the grasshoppers and their ways: their outsides and insides, their hopping and their flying, their egg-laying and the growth and development of the little hoppers; how the birds, and what kinds, stuffed on them, and the robber-flies and the tachina flies and the red mites and the tiny braconids and chalcids attacked them and laid eggs on them, and their grubs burrowed into them; and everything else about them. But all the time the hoppers kept right on eating; at least they did where there was anything left to eat. Stories were told of their following roots of plants and trees down into the ground to eat them; of how they stripped great trees of bark and branches; of how they massed on the warm rails of railroads at nights and stopped trains; of how enterprising towns by offering rewards to farmers collected and killed with kerosene great winrows and mounds composed of innumerable bushels and tons of grasshoppers.

"Some people of active mind and fertile imagination suggested that if the grasshoppers were going to eat up all our usual food, we should learn to eat them! And they got chemists to figure out how much proteids and carbohydrates and hydrocarbons and ash, etc., there was in every little hopper's body. And there was a remarkable dinner given in St. Louis by a famous entomologist to some prominent men of that city, in which grasshoppers were served in several different ways: hopper sautÉ, hopper au gratin, hopper escalloppÉ, hopper soufflÉ, and so on. The decision of the guests—those who lasted through the dinner—was that 'the dry and chippy character of the tibiÆ was a serious objection to grasshoppers as food for man.'

"But you want to know the end of it Mary, don't you? Well, it was a very simple end. Simply, indeed, that the hoppers went back! Yes, actually, when autumn came they all—that is, all that hadn't been eaten by birds and toads and lizards, or collected by farmers and burned, or hadn't got walked on by horses and people, or hadn't got studied to death by entomologists—flew up into the air and sailed back to the Rocky Mountains. Or at least they started that way. I never heard if any of them really got all the thousand of miles back. But whereas in the summer they had all been flying southeast, in the fall they all began flying northwest.

"But some of them had laid eggs in the ground in little cornucopia-like packets before dying or flying away. And much alarm was caused by predictions that millions of new hoppers would come out of the ground in the coming spring and eat all the crops while young, even if the old ones or more like them didn't come again in the summer and eat the mature crops. But these predictions were only partly fulfilled. Not many hatched out in the spring, and those that did seemed to be more anxious to get back to the Rocky Mountains where their brethren were than to eat the Kansas crops. Indeed as soon as the young hoppers got their wings—and that takes several weeks after they come from the egg—they began flying northwest.

"So this remarkable and terrible invasion was over. And all the poor farmers, and the bankrupt or about to be bankrupt storekeepers and bankers and the idle lawyers and doctors and the terrified capitalists and the hard-studying entomologists drew a long breath of relief together."

"But have the hoppers come back any time since 1876?" asks Mary.

"No, that was the last invasion. There had been earlier ones, though, one or two of them just as bad as the Centennial-year one. Indeed Kansas was called the Grasshopper State on account of these terrible summer invasions. There was a bad one in 1866 and another in 1874. The invasions of 1874 and 1876 cost the farmers of the Mississippi Valley at least fifty millions of dollars in crops eaten up."

"But what made them come to Kansas? Why didn't they stay in the Rocky Mountains? It's much more beautiful and interesting there than in Kansas, isn't it?"

"Much, Mary. But it probably wasn't a matter of scenery with these tourist hoppers. Much more likely a matter of food. In those days there were no farmers with irrigated fields on the great plateaus along the eastern base of the Rocky Mountains in Colorado and Wyoming. Nothing much but sage-brush and not overmuch of that grew there. And probably there simply wasn't enough food for all the hoppers. So in seasons when there were too many hoppers or too little food—and if there was one, there was also the other—they flew up into the air, spread their broad wings and sailed away on the winds from the northwest for a thousand miles to Nebraska and Kansas and Texas. And that made an invasion."

"But, then, why didn't they stay there, where there were corn-fields and wheatfields and vegetables?" persisted Mary.

"Mary, I can only tell you what the hard-studying entomologists decided about this, and published along with all the other things they found out, or thought they did, in several big volumes devoted to the grasshoppers. They found out that the hoppers tried to go back because they couldn't stay! That is, odd as it may seem, either the climate or the low altitude or something else uncomfortable about Kansas and Missouri disagrees with the Rocky-Mountain hoppers and they can't live there permanently. They can't raise a family there successfully; at least it doesn't last for more than one generation. They have to live on the high plateaus of the northern Rockies, but they can get on very well for a single summer away from home. Then they must get back if they can. And so it was that the hoppers that came to Kansas solved the weighty problem and relieved the great anxiety of the farmers and the whole country in general as to what was to become of the great grain-fields of the Middle West, by going back home again.

"And will they ever evade Kansas again?"

"That, Mary, is not a question for a stick-to-what-is-known scientific person like me to answer. But as ever since farms and grain-fields and vegetable gardens have been established on the Rocky Mountain plateaus by the farmers who keep moving west, the hoppers haven't come back to Kansas, and as this is probably because they have enough food at home in these Colorado and Wyoming fields, I should be very much surprised if they ever come back to Kansas again."

"Yes, but weren't you surprised that first time you saw them in the Sentinel year?"

"Mary, you are a quibbler. Well, then, I'll say that I don't think they'll ever make another foreign invasion. There!"

It is time for us to stroll home for luncheon. As we get up from under the live-oak, a stumpy-bodied little grasshopper whirs away in front of us.

"To think that such a little thing could make a summer evasion one thousand miles away from here," said Mary.

"Much littler things have done much bigger things," I reply, with my serious manner of lecturer-after-luncheon.