In his buttonhole he wore a yellow dahlia.

It was rather a singular flower for a boutonniere.

The Bradys noticed it at once.

"Look!" whispered Harry. "A yellow dahlia, the flower Mr. Butler was to wear so that we could identify him."

"Yes, but a young man—a mere boy. It must be a coincidence," the old detective replied.

"I don't know, governor. He has evidently spotted you. He is coming this way."

"Can Mr. Butler have sent a substitute?"

The boy approached the table.

He was dark and handsome, slightly undersized, and very well dressed.

"Excuse me," he said in a manly way, addressing the elder detective, "are you Old King Brady?"