Published in Flying Aces, September 1940.
"swiftly, silently, that weird, nameless doom had struck Government flyers. And the victims always looked the same - smiling pleasantly , contentedly, in the very face of Death! Dick Knight tried valiantly to pierce the puzzling shroud of mystery surrounding that unseen menace. But the trail had always led to - nothing. Then out of nowhere on that lonely Laredo field came the sweet, fragrant smell of geraniums, leading the Q-Agent - South of the Border!"