end, it has two on the back of the thorax. At the tail end are two
flaps to help it swim. Even the pupa is never still a minute, but holds
its air-tubes above the water's surface.

"When anything comes to disturb it, it uses its flaps and swims safely
to the bottom of the pool. At the end of two days out of the pupa skin
comes a grown-up mosquito. If it is a Mrs. Mosquito, she promptly begins
to bite people and to carry about fevers or malaria from person to
person. The bite of a mosquito may sometimes be as dangerous as the bite
of a rattlesnake."

The children had been slapping the mosquitoes buzzing about on the
_piazza_. "And now," said the guide, "before we go into supper, I will
tell you a real and a true story. Mosquitoes sometimes carry sickness
from one person to another until it spreads throughout a large city. We
didn't realize how dangerous mosquitoes were till a short time ago.
People had malaria, and were very ill with it. In some countries many
died. Every one thought, however, that the malaria came in some
mysterious way from the mists of the low-lying swamps and marshes. But
one day some one happened to think it might not be in the marshes, after
all; rather that it might be a certain little two-winged insect with a
short, piercing instrument, which spent its babyhood days in these same
marshes.

"And so two English doctors determined to find out the truth of the
matter. In the faraway land of Italy was a place where thousands of
people were suffering from this disease. There these doctors went and
built a comfortable little house in the very worst place they could
find. They were careful to screen every door and window, and to leave
not a crack for a mosquito to crawl in.

"There they lived, always going into the house at sundown, shutting all
the screen doors, but allowing the damp night air to pour in. It was
this night air which every one supposed gave people malaria. But the two
physicians in the snug little house, free from mosquitoes, kept well,
strong, and happy, although the people outside in the other houses were
very ill and suffering with chills and fever.

"You see, these little Anopheles, for that is their name, bite some one
ill with malaria. Perhaps the next person they stab with their sharp
needle is well. In this way they leave some of the poisoned blood in the
wound. There is another illness which is a hundred times worse than
malaria. This is called yellow fever. In some countr