ne
group of mosquitoes carries the germs. The two common groups are the
straight-backed and the humped. To prove that the straight-backed ones
did the harm several of them were allowed to suck blood from a man
sick with malaria in Italy. They were then sent to London and let
bite a healthy man. In a few days he became sick with malaria. Many
experiments with the humped-back mosquitoes, found nearly everywhere
in our country, show that they do not carry malaria germs.

=Yellow Fever.=--Until 1901 yellow fever was the scourge of many
cities in the South. Thousands of persons lost their lives from it.
Wherever the dread disease broke out in a city many persons would flee
to the country because they thought that they could not breathe the
air without getting the germs.

Some persons thought that mosquitoes might cause the disease, and in
1900 experiments were carried out in Cuba to learn whether mosquitoes
really did carry yellow fever germs. Seven men made their home in a
room well screened to keep out the mosquitoes. They used clothing
which had been worn by others sick with the fever and even slept on
pillows and blankets on which yellow fever victims had died. Many
persons thought that these bedclothes were full of fever germs and
that all the men would surely get the disease. Not one of them,
however, got sick although they lived in the midst of these soiled
materials for three weeks.

[Illustration: FIG. 75.--The yellow fever mosquito biting the finger.
Note how the lower lip is bent.]

Seven other men were chosen for another experiment. A large room was
prepared and made thoroughly clean. Only clean bedding and clean
clothes were used. The men were given pure food and pure water, but
into the room were let loose mosquitoes which had been sucking blood
from a person sick with the fever. In a few days six of the seven men
became sick with the fever and one of them died. From these
experiments and other studies we now know that _this dreadful fever is
carried from the sick to the well only by the bites of mosquitoes_.

[Illustration: FIG. 76.--A bunch of mosquito eggs floating on the
surface of the water. Enlarged about fifteen times.]

=How Mosquitoes Live.=--Before we can get rid of any pests we must
know where the eggs are hatched and the young pass their early life.
The eggs of mosquitoes are laid on standing water. The water may be in
an old tomato can, a rain barrel, a cistern, or a large pond. A day or
tw