"Yes, please," said Mary.

"Well, I had been studying in a great university in an old German town all the spring and early summer and had come to Switzerland for my vacation. You know there are splendid mountains there—"

"The Alps," interrupted Mary. "The highest is Mt. Blanc, 15,730 feet above the sea."

How Mary does know her geography!

"And beautiful lakes," I continue. "And the roads are good for tramping, and the hotels cheap. Anyway, the ones the students go to. I had come to Lucerne from Zurich—"

"Noted for its silks and university where women can go," Mary broke in again.

Bless me, what's the use of going to Europe anyway, if you learn everything about everywhere in the grades?

"And had gone straight to the MÜhlenbrÜcke," I go on,—"that's the old bridge all covered with a roof that crosses the Reuss only a few rods from where it flows out of the lake; the lake of Lucerne, you know."

"Of course," said Mary.

"For it is on the ceiling of that bridge," I persist, "that these curious old Dance of Death pictures are painted, and I had heard a great deal about them. They show how everybody is dancing through life to his grave. Not very pleasant pictures, Mary."

"Very unpleasant, I should think," says Mary, positively. "I hope you didn't look at them long."

"No, because, for one reason, it was getting too dark to see them. The sun had set behind the Gutsch—that's a pretty hill just west of Lucerne—and the electric lights were already flashing along the lake-shore promenade. You know what a wonderfully beautiful lake Lucerne is, of course, Mary?"

"Yes; it is unsurpassed in Switzerland, perhaps in Europe, for magnificence of scenery," replies Mary, in level voice.

I resolve to cut geographic information out of any further stories I tell Mary. Do they commit Baedeker to memory nowadays in the schools?

"Exactly," I manage to reply without betraying too much astonishment at this revelation of the American educational method.

"Well, along the shore of this unsurpassed lake at the town of Lucerne there is a broad promenade with trees and benches and electric lights. Behind it are the big hotels all in a curving row, and after dinner all the people come out and stroll about while the band plays. It is a fine sight."

Mary seemed to be getting a little less than interested. She squirmed into a new position on the rough rockwork and then, looking out over the little pond with its hawking dragons whizzing back and forth, she asked: "What about the May-flies, please?"

I really believe she knew all about the hotels and promenade and the band. What wonderful schools!

"I was coming—I have just come to them," I reply with dignity.

I am a professor and have a certain stock supply of dignity to draw on when necessary. It isn't often necessary with Mary.

"Well, as I came from the covered MÜhlenbrÜcke and out on to the lake-shore promenade, I saw a little crowd of people gathered under and about a brilliant arclight hanging in an open place in front of the great Schweizerhof Hotel. The light seemed to me curiously hazy, and even before I got near the crowd I had made a guess at what was going on. My guess that it was a May-fly dance of death was quite right. Perhaps it would really be better to call it a 'dance of life,' for it really was sort of a great wedding dance. But it was a dance of death, too, for the dancers were falling dead or dying out of the dizzying whirly circles by thousands. How many hundreds or thousands or millions of May-flies there were in the dense circling cloud about the light, I have no idea. But the air for twenty feet every way from the light was full of them, and the ground for a circle of thirty or forty feet underneath was not merely covered with the delicate dead creatures, but was covered for from one to two inches deep!

"The crowd of promenaders looked on in gaping wonder. Not one seemed to know what kind of creature this was, nor of course anything about what was really going on; that this was all of the few hours of feverish life which these May-flies enjoyed in their winged state, and that they gave it all up to the business of mating and egg-laying; where they came from, how they had lived before, why they should be here to-night and no other in the whole year, all these things which it seems to me the onlookers ought to have wanted to know, nobody seemed to know, nor anybody seemed particularly to care to.

"But there are places in the world where the people do want to know these things, and a great many more, about the May-flies. One such place is the Thousand Islands in the St. Lawrence River. One day I was sailing down this river among the Thousand Islands, and the acquaintanceship of a small and unusually delicate kind of May-fly was forced on me by the hundreds of them that persisted in alighting on my clothes, my hat, and my hair. They kept walking unsteadily about over my face and hands and the open pages of the book I was trying to read. And they kept dying, dying, all around. One would light on the outer edge of the page, and before it had walked across to the beginning of a sentence, it would die and its body would slide gently down into the back of the book and—be a bookmarker!"

"That's not a very nice way to talk about the poor little dead May-flies," said Mary, rather seriously.

"It isn't, Mary, I know," said I. "But we've got to relieve the gloom of this tale someway, don't you think? There is too much wholesale death in it to suit my publisher! And so I am trying to introduce a little jocularity into it, don't you see, Mary?"

"People are not supposed to be very funny at funerals," said Mary, severely. "Where did the little Thousand Islands May-flies come from, and why do the people there want to know about them?"

"Because there are so many May-flies that they are a great pest. Not by eating crops—for there aren't any, I suppose, and the May-flies don't eat anything anyway—nor by carrying malaria, but just by living and dying all over; everywhere in one's summer cottage, down on the river-bank where you are watching the sunset, under the trees when you are lying in your hammock and trying to read, in your rowboat when you are paddling about to visit your neighbors on other islands. To be walked on and died on by hundreds and hundreds of little flies, and all the time, grows to be very uncomfortable. So the May-flies or river-flies or lake-flies as they are variously called are cordially hated by all the Thousand-Islanders and the St. Lawrence-Riverers. And the people want to know about where they come from, and how they live, and all about them, indeed, so as to try to find some way to be rid of them."

"And do you know where they come from, and how they live, and all about them," asks Mary, with a slightly roguish manner, I fear.

"Well, I know something. In the first place, after the dance of death, the few that don't die fly out over the lake or river or pond and drop a lot of little eggs into it. Then they die happy—if May-flies can be happy. Mind you, I don't say they can. We are the only animals that we know can be happy. And we mostly aren't. From the eggs hatch young May-flies without wings or long thread-like tails, but just little, flat, under-water creatures with gills along the sides so they can breathe without coming up to the surface. Some kinds burrow into the mud at the bottom, some kinds make little tubes or cases in which to live, while others stay mostly on the under side of stones. They eat little water-plants or broken-up stuff they find in the water, although some eat other little live animals, even other young May-flies. And many of them get eaten themselves. They are favorite food of the under-water dragons. You remember, don't you, Mary, how our dragons of Lagunita would snap up the young May-flies in Monday Pond?

"Well, these young May-flies—the ones that don't get eaten by dragons, stone-flies, water-tigers, and other May-flies—grow larger slowly, and wing-pads begin to grow on their backs. In a year, maybe, or two years for some kinds, they are ready for their great change. And this comes very suddenly. Some late afternoon or early evening thousands of young May-flies of the same kind, living in the same lake or river, swim up to the surface of the water, and, after resting there a few moments, suddenly split their skin along the back of the head and perhaps a little way farther along the back, and like a flash squirm out of this old skin, spread out their gauzy wings and fly away. They do this so quickly that your eye can hardly follow the performance."

"And then they all fly to the light and begin their dance of death," breaks in Mary.

"No, wait; they are not yet quite ready for that. First, they do a very unusual thing; something that no other kinds of insects have ever been seen to do. This is it: They fly away to a plant or bush or tree at the water's edge, and there they cling for a little while and then cast their skin again."

"The new skin they have just got, with the wings and everything?" asks Mary.

"Exactly; the new skin. It comes off of the wings, off of the long tails and the short feelers, and all the rest of the body. No other kind of insect but the May-fly casts its skin once its wings are outspread. But now the May-fly is ready for its dizzy dance. And as it has only a few hours to do it in, it usually starts as soon as there are any lights to dance about. Think of it, to come up from under the water, get your wings and be a real May-fly, not just a crawling thing on the bottom of a pond, and have only one evening to live in! Probably to dance the whole evening through is about the best thing to do under such circumstances."

"Don't any of the poor May-flies live for more than one evening?" asks Mary. "It does seem a shame to put in so long a time, one year, two years for some, getting ready to fly and then have only one evening or night for flying."

"Well, yes, some do, Mary. That is, there are many different kinds of May-flies; some large ones, some small ones, some kinds with four wings, some kinds with only two, and the length of the flying time is not the same for all these kinds. Some live a day, some two, some perhaps even three or four. But there are several kinds whose flying life is just a few hours; they are born, that is, as flying creatures, after sundown and they die before the next sunrise. The first kind of May-fly whose life was ever carefully studied—this was nearly two hundred and fifty years ago, by a famous naturalist of Holland—lives only five hours after it comes from the water. But remember what a fine long time they have being young! If we could be young—but there, that's foolish. Mary, the chimes in the tower-clock are sounding. Listen!"

And we sit perfectly still and hear the beautiful Haydn changes on the four bells, and then count twelve clear strokes of the big clock-bell that come all the way from the Quadrangle to us, softened and mellowed by the distance. We must go home to luncheon. And after luncheon I must go and lecture—Ugh! How sad!—sad for the students and sad for me. But that's the way we do it, and until we find the real way, we must all continue to suffer together.

"Come, Mary, we're off. How would you like to be a May-fly?"

"And have only one day to live when I'm all grown up?"

"You might be saved some troubles, Mary."