d's comment
after he had inspected the riders carefully for a couple of
minutes.

"That's what I thought," from Billie. "They look like a bunch of
_vaqueros_ to me; but what would a crowd of fifty cowpunchers be
doing in a country where the only cattle are goats?"

"That's right!" laughed Donald, greatly amused at Billie's odd
expression, "but still that is what they appear to be. Perhaps
they are expecting a drove of cattle up on the train."

"More likely they are expecting a load of bullion going down to
the City of Mexico," remarked the third of the party. "What do
you think, Pedro?" turning to the fourth of the boys who composed
the quartette.

"I am afraid you are right, Adrian," replied Pedro, with an
accent which denoted that of the four he was the only one who was
not of an English-speaking race.

"You don't think they would hold up a train in broad daylight,
and that not more than five miles from town, do you?" queried
Billie.

"If they are what I suspect," declared Pedro, "I think they would
hold it up at the station, if there were only a few more of
them."

"And what do you think they are?"

"I think they are Zapatistas."

"What are they?" asked Donald.

"Followers of the bandit leader, Emilio Zapata."

"Which side does he belong to?" asked Adrian. "Huerta or
Carranza?"

"Neither. He is simply a bandit, and his followers prey upon any
whom they find unprotected."

"And do you really think they are going to hold up and rob the
train from Pachuca?"

"_Sin duda!_" meaning without doubt.

"Then we must prevent them," declared Donald emphatically.

"What business is it of ours?" asked Billie. "If one bunch of
Mexicans wants to rob another bunch, especially if the second
bunch are Huertistas, I don't know that it is for us to
interfere. I'm not looking for trouble."

"You're not afraid, are you? If----"

"Say, Don," interrupted Billie, "what's the use of always asking
such foolish questions? If I remember rightly, the last time you
asked me that question was up on the Rio Grande a year ago, about
the time that I was swimming rivers and breaking into prisons
with the Texas Rangers to get you and Ad out of trouble. Now
why----"

Donald held up both hands.

"That's enough, Billie," he laughed. "I'll take it all back. Of
course you're not afraid. But I insist we must prevent this
hold-up."

"And again I ask, why?"

"Because there may be women and children on the train and----"

"Tha