"Pardon," the two Duponts joined in. They had been listening for the last few minutes. "The lady is dead, you say, and there is a mark on the neck?"

It was Jean, the younger Dupont, who spoke:

"May I make a suggestion? There was a wasp flying about. I killed it." He exhibited the corpse in his coffee saucer. "Is it not possible that the poor lady has died of a wasp sting? I have heard such things happen."

"It is possible," agreed Bryant. "I have known of such cases. Yes, that is certainly quite a possible explanation. Especially if there were any cardiac weakness."

"Anything I'd better do, sir?" asked the steward. "We'll be at Croydon in a minute."

"Quite, quite," said Doctor Bryant as he moved away a little. "There's nothing to be done. The - er - body must not be moved, steward."

"Yes, sir, I quite understand."

Doctor Bryant prepared to resume his seat and looked in some surprise at the small, muffled-up foreigner who was standing his ground.

"My dear sir," he said, "the best thing to do is to go back to your seat. We shall be at Croydon almost immediately."

"That's right, sir," said the steward. He raised his voice: "Please resume your seats, everybody."

"Pardon," said the little man. "There is something -"

"Something?"

"Mais oui, something that has been overlooked."

With the tip of a pointed patent-leather shoe, he made his meaning clear. The steward and Doctor Bryant followed the action with their eyes. They caught the glint of orange and black on the floor, half concealed by the edge of the black skirt.

"Another wasp?" said the doctor, surprised.

Hercule Poirot went down on his knees. He took a small pair of tweezers from his pocket and used them delicately. He stood up with his prize.

"Yes," he said, "it is very like a wasp, but it is not a wasp."

He turned the object about this way and that, so that both the doctor and the steward could see it clearly - a little knot of teased fluffy silk, orange and black, attached to a long peculiar-looking thorn with a discolored tip.

"Good gracious! Good gracious me!" The exclamation came from little Mr Clancy, who had left his seat and was poking his head desperately over the steward's shoulder. "Remarkable - really very remarkable - absolutely the most remarkable thing I have ever come across in my life. Well, upon my soul, I should never have believed it."

"Could you make yourself just a little clearer, sir?" asked the steward.

"Do you recognize this?"

"Recognize it? Certainly I recognize it." Mr Clancy swelled with passionate pride and gratification. "This object, gentlemen, is the native thorn shot from a blowpipe by certain tribes - er - I cannot be exactly certain now if it is South African tribes or whether it is the inhabitants of Borneo which I have in mind. But that is undoubtedly a native dart that has been aimed by a blowpipe, and I strongly suspect that on the tip -"