SCOUTING FOR GIRLS 
449 
Among the injurious insects a few may be mentioned: 
the House Fly or Filth Fly, which may carry disease 
germs on its feet to the food that we eat ; the mosquitoes, 
which transmit yellow fever and malaria, the rat flea, 
which carries bubonic plague ; the weevils, which destroy 
rice, beans, chestnuts, etc., and the plant lice, or aphids, 
which, by sucking the juices from ornamental and food 
plants, are among the most destructive of all insects. 
There are so many insects in the world that we cannot 
hope to learn them all, even if we wanted to do so, but 
most of us wish to know the names of those that attract 
our attention, and to know what they do that is im- 
portant or interesting. There are approximately 400,000 
species or kinds of insects known in the world; that is, 
about three times as many as there are species or kinds 
of all the rest of the animals in the world put together. 
This fact should not hinder us from making a start and 
becoming familiar with the interesting habits of a few 
of the insects about us. 
The eggs of the Monarch Butterfly may be collected 
upon the milkweed and brought in, so that the whole 
life history or metamorphosis of this beautiful insect, 
from the egg through the larva or caterpillar stage and 
the pupa or chrysalis stage to the adult butterfly, may be 
watched. The larvae or caterpillar must be supplied 
daily with fresh milkweed leaves. Other butterflies and 
moths and many other insects may be reared in the same 
way by supplying the larvae with suitable food. If we 
should find a caterpillar feeding upon the leaves of a 
maple tree we should continue to feed it maple leaves 
if we wish to rear it. Silkworms will eat the leaves of 
Osage-orange, but they seem to prefer mulberry leaves. 
Cocoons of moths may be easily collected in winter 
after the leaves have fallen, and brought in and kept in 
