"Bad, bad!" she mimicked him, indulgently. "You know that gentlemen are not allowed to ask ladies questions like that on Mars."
"I shall never understand your Martian ways," he said. "In my world it is the other way round."
“Barbarity," she murmured, with a shiver, but added, "how quaint!"
Don frowned. He was still unable to understand her. Several times she had told him that she loved him and promised to marry him, always in a casual manner as though it were a mere trifle. When he tried to pursue the subject she cut him short, pretending to be annoyed. Martian conventions were very strict on men, and the ways of Martian girls beyond understanding.
"Don't be impatient, Don," she said. "One day you shall be my husband and the greatest in all Mars. Our Eugenics Control approves Earth-Mars unions saying that fresh blood from another planet will put new virility into our race. We need it, after our thousands of years of underground life."
Which Don thought was queerly cold-blooded talk.
"Then why the delay? Why can't we be married now?"
For a while she did not answer.
"I'd like to,” she said at last, "but first there is much to do. I cannot think of my private feelings while the whole civilization of Mars is in danger."
Her words startled him with their unexpectedness.
"Is it in danger, then? I don't follow Martian news much. I don't understand it too well. I knew you were having trouble with savage animals lately. Packs of ferocious apes, I understand, have attacked and destroyed several cities. But is it as serious as that?"
"It is," she said. "These apes, you see, Don, are half human. Like the snakes and the rats, they breed in the innumerable smaller caves of our world, so many of which are too small, too dangerous or too rambling to be explored. In some places they have been a terrible pest. A section of Mars many thousands of cubic miles in extent has been solely occupied by them for generations. And slowly, because of their depredations, their killings and their kidnapings, the people of Mars have had to fall back until the area occupied by the apes has increased to several times its original size. And the larger the area they occupy the faster their numbers increase.
But lately our trouble has assumed a new and terrible form. The ape-men have suddenly become much more daring than ever before. There appear to be far more of them than anyone had ever dreamed, and they are attacking whole cities. And although we thought that the defenses of our cities were ample against such creatures, yet they have completely overwhelmed town after town. Sentries at gates and on city walls tell us that their deathray boxes suddenly go out of action as soon as they try to use them on the apes. Watch."
PRINCESS WIMPOLO twirled knobs. From a recess a blue light glowed. The television clicked into action.
In the globe they saw a picture, three dimensional and colored, of a vast Martian cavern. What appeared to be pillars of fire shooting up out of the ground lighted the view. Actually they were carved pillars treated with the cold light that the Martians used so liberally.
A beautiful city was before them. Many of the walls had fallen down. Many roofs were caved in. In the place of men shaggy caricatures of human beings, long-armed, short-legged, bar-
