"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.
