“You needn’t jump out of your skin on my account,” said Miss Polly Brewster, with a gracious smile.  “I’m not a devilkin.”

“You are!  That is—­I mean—­I—­I—­beg your pardon.  I—­I—­”

“The poor man’s having another bashful fit,” she observed, with malicious glee.  “Did the bold, bad, forward American minx scare it almost out of its poor shy wits?”

“You—­you startled me.”

“No!” she exclaimed, in wide-eyed mock surprise.  “Who would have supposed it?  You didn’t expect me down here, did you?”

Thereupon she got a return shock.

“Yes, I did,” he said; “sooner or later.”

“Don’t fib.  Don’t pretend that you knew I was here.”

“W-w-well, no.  Not just now.  B-b-but I knew you’d come if—­if—­if I pretended I didn’t want you to long enough.”

“Young and budding scientist,” said she severely, “you’re a gay deceiver.  Is it because you have known me in some former existence that you are able thus accurately to read my character?”

“Well, I knew you wouldn’t stay up there much longer.”

“I’m angry at you; very angry at you.  That is, I would be if it weren’t that you really didn’t mean it when you said that you really didn’t want to see my face again.”

“Did any one ever see your face once without wanting to see it again?”

“Ah, bravo!” She clapped her hands gayly.  “Marvelous improvement under my tutelage!  Where, oh, where is your timidity now?”

“I—­I—­I forgot,” he stammered, “As long as I don’t think, I’m all right.  Now, you—­you—­you’ve gone and spoiled me.”

“Oh, the pity of it!  Let’s find some mild, impersonal topic, then, that won’t embarrass you.  What do you do under the shadow of this rock, in a parched land?”

“Work.  Besides, it isn’t a parched land.  Look on this side.”

Half a dozen steps brought her around the farther angle, where, hidden in a growth of shrubbery, lay a little pool of fairy loveliness,

“That’s my outdoor laboratory.”

“A dreamery, I’d call it.  May I sit down?  Are there devilkins here?  There’s an elfkin, anyway,” she added, as a silvered dragon-fly hovered above her head inquisitively before darting away on his own concerns.

“One of my friends and specimens.  I’m studying his methods of aviation with a view to making some practical use of what I learn, eventually.”

“Really?  Are you an inventor, too?  I’m crazy about aviation.”

“Ah, then you’ll be interested in this,” he said, now quite at his ease.  “You know that the mosquito is the curse of the tropics.”

“Of other places, as well.”

“But in the tropics it means yellow fever, Chagres fever, and other epidemic illness.  Now, the mosquito, as you doubtless realize, is a monoplane.”

“A monoplane?” repeated the girl, in some puzzlement.  “How a monoplane?”

“I thought you claimed some knowledge of aviation.  Its wings are all on one plane.  The great natural enemy of the mosquito is the dragon-fly, one of which just paid you a visit.  Now, modern warfare has taught us that the most effective assailant of the monoplane is a biplane.  You know that.”