o after the mother lays one or two hundred eggs, they hatch into
dark, wriggling objects called _wigglers_. In from ten to twenty days
later they change into flying mosquitoes. These habits of life show
that the easiest time to kill them is when they are young.

[Illustration: FIG. 77.--Photograph of wigglers, the stage in which
the mosquito lives a week or two in water.]

=Getting rid of Mosquitoes.=--During warm weather mosquitoes cause the
death of more than a thousand persons in the world every day besides
making many others very sick. To get rid of mosquitoes is to prevent
sickness and death. In one year yellow fever killed over five thousand
people in New York and Philadelphia because the doctors did not know
how to stop the disease from spreading.

When this fever broke out in New Orleans in 1905, less than five
hundred persons died of it because the doctors had then learned that
the disease is spread only by the yellow fever mosquito. They
therefore began killing the mosquitoes. Kerosene was poured over all
the ponds and stagnant pools of water which could not be drained. This
kills the young mosquitoes because the oil gets into their breathing
tube which they stick up to the surface of the water to get air. All
rain barrels and tin cans were emptied and cisterns were tightly
covered. Men, women, and children worked week days and Sundays killing
mosquitoes because they knew that they were saving human life. The
destroying fever was stopped.

[Illustration: FIG. 78.--Photograph of eggs laid on waste matter by
two flies in one hour.]

=Flies cause much Sickness.=--Very few people are afraid of house
flies because they do not bite. Although they are so small and
seemingly harmless yet we know that they cause many more deaths every
year than mad dogs, poisonous snakes, and all wild beasts.

Flies crawl around among slops, in spittoons, and in other unclean
places. In this way they get thousands of germs of tuberculosis,
typhoid fever, and cholera on their feet and then scatter them over
our food as they crawl about on the table, in the grocery store, or
among the milk cans. In our last war with Spain more than a thousand
of our soldiers were made sick with fever carried to them by flies.

In Denver, Colorado, in 1908 fifty persons were made sick with the fever
by flies which fed on the slops from a sick room and then crawled
around in the milk cans from which those who became sick used milk.

[Illustration: