INTRODUCTION 
I T is only within the last twelve years that the dan¬ 
gerous character of the common house fly has been 
known; and only within the last two years have the 
people at large begun to wake up to this danger and 
to inquire concerning the means by which this fly can 
be kept down. The writer published some account 
of its life history in a bulletin on household insects 
published by the U. S. Department of Agriculture in 
1896. Later he made some experiments with regard 
to remedies, and in 1900 published a rather lengthy 
paper on the insect fauna of human excrement with 
especial reference to the carriage of typhoid fever by 
flies. Within the last two years, however, articles 
relating to the so-called house fly in connection with 
its disease-carrying possibilities have been published 
literally by the thousand, and this interest, perhaps 
having its origin in the United States, has spread to 
nearly all parts of the civilized world, and yet in no 
one of these published articles is the whole story told. 
No one can find in condensed and convenient shape 
the general information he desires in regard to this 
insect. The publishers of this book, realizing this fact, 
have invited the author to attempt to fill this want. 
This book is not intended to be a scientific mono¬ 
graph ; it is simply an attempt to tell in an understand¬ 
able way what is known about the subjects indicated 
in the title. 
xv 
