A group of riders appeared down the road.  The lean man brushed a cloud of smoke away and gazed at them with indifference.  They drew nearer.  He saw that they were Mexicans—­rurales.  Without turning his head, he called to an invisible somebody in the next room.

“Jack, drift over to the cantina and get a drink.”

A chair clumped to the floor, and a stocky, dark-faced man appeared, rubbing his eyes.  “On who?” he queried, grinning.

“On old man Diaz,” replied the lean man.

“All right, Pat.  But mebby his credit ain’t good on our side of the line.”

The lean man said nothing.  He continued to gaze out of the window.  The white road ran south and south into the very haze of the beyond.  His assistant picked up a hat and strolled out.  A few doors down the street stood several excellent saddle animals tied to the hitching-rail in front of the cantina.  He didn’t need to be told that they were the picked horses of the rurales, and that for some strange reason his superior had sent him to find out just why these same rurales were in town.

He entered the cantina and called for a drink.  The lithe, dark riders of the south, grouped round a table in one corner of the room, glanced up, answered his general nod of salutation indifferently, and turned to talk among themselves.  Catering to authority, the Mexican proprietor proffered a second drink to the Americano.  The assistant collector toyed with his glass, and began a lazy conversation about the weather.  The proprietor, his fat, oily face in his hands and his elbows on the bar, grunted monosyllables, occasionally nodding as the Americano forced his acknowledgment of a highly obvious platitude.

And the assistant collector, listening for a chance word that would explain the presence of armed Mexico on American soil, knew that the proprietor was also listening for that same word that might explain their unprecedented visit.  Presently the assistant collector of customs began a tirade against Nogales, its climate, institutions, and citizens collectively and singly.  The proprietor awoke to argument.  Their talk grew loud.  The assistant collector thumped the bar with his fist, and ceased talking suddenly.  A subdued buzz came from the corner where the rurales sat, and he caught the name “Waring.”

“And the whole town ain’t worth the matches to burn it up,” he continued.  “If it wasn’t for Pat, I’d quit right now.”  And he emptied his glass and strode from the room.

Back in the office, he flung his hat on the table and rumpled his hair.  “Those coyotes,” he said casually, “are after some one called Waring.  Pablo’s whiskey is rotten.”

The collector’s long legs unfolded, and he sat up, yawning.  “Jim Waring isn’t in town,” he said as though to himself.

“Pat, you give me a pain,” said the assistant, grinning.

“Got one myself,” said the collector unsmilingly.  “Cucumbers.”