as delighted at finding himself with his old friend again, and
he seized the opportunity gladly of asking him how he happened to find
out that the pest had got a start.

"I was campin' last night," said the old Ranger, "an' I saw an old dead
tree that looked as if it might have some tinder that would start a
fire easy. So I picked up my ax an' went up to it. But the minute I got
there I felt somethin' was wrong, so I sliced along the bark, an' there
were hundreds of the beetles. Then I looked at some of the near by
trees, an' there was a few, here and there. But the funny part of it was
that although I looked, an' looked carefully, for a hundred yards on
either side, I couldn't find any more."

"So much the better," said Wilbur, "you didn't want to find any more,
did you?"

The old hunter stepped over to a spruce and examined it closely.

"I didn't think there were any there," he said, "but you can't be too
sure."

They walked all the rest of the morning, without having seen a sign of
any beetles, though once the most distant party whooped as a sign that
some had been found.

"I remember," said the Ranger, "one year when we had a plague o'
caterpillars. They was eatin' the needles of the trees an' killin' 'em
by wholesale. There was nothin' we could do to stop it. But it got
stopped all right."

"How?" Wilbur queried interestedly. "Rain?"

"Rain would only make it worse. Have you ever noticed, son, that when
somethin' pretty bad comes along, there's always somethin' else comes to
sort o' take off the smart? Nothin's bad all the time. Well, this time,
there came a fly."

"A fly?"

"Yes, son, a fly, lookin' somethin' like a wasp, only not as long as
your thumb-nail. They come in swarms, an' started disposin' o' them
caterpillars as though they had been trained to the business. They stung
'em an' then dropped an egg where they'd stung. Sometimes the
caterpillar lived long enough to spin a web, as they usually do, but it
never come out as a moth. An' since it's the moth that lays the eggs,
this fly put an end to the caterpillar output with pleasin' swiftness."

"What did they call the fly?"

"I did hear," said Rifle-Eye, thinking. "Oh, yes, now I remember; it was
the ik, ik--"

"Oh, I know now," said Wilbur; "I remember hearing about it at the
Ranger School. The ichneumon fly."

"That's it. But, as I was sayin'--" he stopped short. Then the old
hunter took a quick step to one side, pointed at a pine tree,