Ned, observing the lad's position, suddenly conceived a mischievous plan. Unnoticed by the others, he permitted his own pony to fall back until he was a short distance behind Stacy. The others were a little way ahead.
Ned rode slowly alongside his companion, as he passed, bringing the rowel of his spur sharply against the withers of Chunky's mount.
The effect was instantaneous.
The fat boy's mount, itself half asleep, suddenly humped its back, and with bunching feet leaped clear of the ground.
"Hello, what's the matter back there?" called Ned, who by this time was a full rod in advance of his companion.
Stacy did not answer. He was at that moment turning an undignified somersault in the air, his pony standing meekly, awaiting the next act in the little drama.
The fat boy landed on the plain in a heap.
"Are you hurt, Chunky?" cried Tad anxiously, slipping from his saddle and running to his companion.
"I—I dunno, I—I fell off, didn't I?"
"You're off, at least," grinned Ned. "What was the matter?"