A few yards behind the rural, Ramon reined up.  Slowly he lowered the muzzle of his gun.  The rural called the name of one of his fellows.  The answer came in a blunt crash, which rippled its harsh echoes across the sounding hills.  The rural flung up his arms and pitched forward, rolling to Waring’s feet.  The gunman leaped up, and, snatching his carbine from the rock, swung round and took his six-gun from the rural’s limp fingers.  Plunging to the brush beyond the pocket, he swung to the saddle and shot down the slope.  Behind him he could hear Ramon’s horse scattering the loose rock of the hillside.  A bullet struck ahead of him and whined across the silence.  A shrill call told him that the pursuers had discovered the body of their fellow.

Dex, with ears laid back, took the ragged grade in great, uneven leaps that shortened to a regular stride as they gained the level of the valley.  Glancing back, Waring saw Ramon but a few yards behind.  He signaled to him to ride closer.  Together they swung down the valley, dodging the low brush—­and leaping rocks at top speed.

Finally Waring reined in.  “We’ll make for that ridge,”—­and he indicated the range west.  Under cover of the brush they angled across the valley and began the ascent of the range which hid the western desert.

Halfway up, Waring dismounted.  “Lead my horse on up,” he told Ramon.  “I’ll argue it out with ’em here.”

“Senor, I have killed a man!” gasped Ramon.

Waring flung the reins to his companion.  “All right!  This isn’t a fiesta, hombre; this is business.”

Ramon turned and put his horse up the slope, Dex following.  Waring curled behind a rock and swept the valley with his glass.  The heads of several rurales were visible in the brush.  They had halted and were looking for tracks.  Finally one of them raised his arm and pointed toward the hill.  They had caught sight of Ramon on the slope above.  Presently three riders appeared at the foot of the grade.  It was a long shot from where Waring lay.  He centered on the leading rural, allowed for a chance of overshooting, and pressed the trigger.  The carbine snarled.  An echo ripped the shimmering heat.  A horse reared and plunged up the valley, the saddle empty.

Waring rose, and plodded up the slope.

“Three would have trailed us.  Two will ride back to the railroad and report.  I wonder how many of them are bushed along the trail between here and Nogales?”

In the American custom-house at Nogales sat a lean, lank man gazing out of a window facing the south.  His chair was tilted back, and his large feet were crossed on the desk in front of him.  He was in his shirt-sleeves, and he puffed indolently at a cigar and blew smoke-rings toward the ceiling.  Incidentally his name was known throughout the country and beyond its southern borders.  But if this distinction affected him in any way it was not evident.  He seemed submerged in a lassitude which he neither invited nor struggled against.