number of vicious wasps
were buzzing about them.

"They're wasps, with the worst stings of any I ever saw!" yelled the
professor. "That's why I want to get away. I was stung by one of them
once, and I'll never forget it. Look out! Here come more of 'em!"

There was a cloud of the wasps flying about Bob, Jerry, and the
professor now, and the tall lad noted that the insects were also
hovering around other soldiers and officers. There was a black cloud
of them near the small case that had caused such a scare.

"Was that what was in the black box?" asked Jerry, as he dodged a wasp
that seemed about to alight on his nose.

"Yes. Wasps," asserted the scientist. "The most war-like wasps I have
been able to discover in this part of Europe. They are a cross breed
of the _Vespidae Polistes_, _Eumenes_, and _Odynerus_, and for stings
are not to be equalled."

"Wasps!" cried Jerry, as he swung and swatted at some still buzzing
around him. "What in the world did you expect to do with them,
Professor Snodgrass? And why did you have them in the black box?"

"I had them to show to one of the headquarters officers," was the
answer. "But I think I had better postpone the explanation until we
get rid of our pursuers. Let's go under those bushes. I think we
shall be safe then," and the professor unceremoniously dived under a
clump of shrubbery, an example followed by Jerry and some of the
others.

Ned and Bob, who had managed to accompany the professor and their tall
chum, were stung several times before they, also, found shelter
beneath the thick leaves, and howls of pain from a number of soldiers
indicated that they, too, felt the stings of the insects.

For a while there was as bad a rout of the headquarters staff as if
the Germans had overwhelmed it. But finally the insects were
dispersed, most of them flying off to the woods, while those that
remained were beaten off, so that the officers and men began to drift
back again. The professor and the Motor Boys came out of hiding, and
then curious looks began to be cast at the scientist and the black
box, which was now empty. The displaced cover showed how the wasps had
gotten out.

"Is this the new weapon for causing a German retreat that you promised
to show me?" asked the colonel of the professor, trying not to smile
as he put the question.

"Yes," answered Professor Snodgrass, "it is. I am sorry, but I am
afraid there are no specimens left to show you. Some one must have
t