CHAPTER XVIII 
INSECTS AND DISEASE 
HROUGHOUT this book reference is constantly 
made to the injuries done by insects to our 
forest-trees, flowers, fruits, vegetables, and 
grains. The millions of dollars lost annually 
because of the sap-sucking of the San Jose 
scale, the grape-phylloxera, the chinch-bug, 
and the Hessian fly, and the biting and chewing 
of beetles and caterpillars, grubs and borers, 
are a sort of direct tax paid by farmers and 
fruit-growers for the privilege of farming and growing fruit. If this tax 
were levied by government and collected by agents with two feet instead 
of being levied by Nature and collected by six-footed agents, what a swift 
revolt there would be! But we have, most of us, a curious inertia that leads 
us to suffer with some protesting complaint but little protesting action the 
“ways of Providence,” even when we fairly well recognize that Providence 
is chiefly ourselves. 
When we reflect on the four hundred millions of dollars a year lost to 
our pockets by insect ravages we may incline to believe that the only kind 
of insect study which should claim our attention is the study of how to rid 
our lands of these pests. We may be excused for affirming of bugs, as was 
said of Indians by some epigrammatist, that the only good ones are the 
dead ones. When, however, we learn, as we are learning in these present 
days, that insects are not simply serious enemies of our crops and purses, 
but are truly dangerous to our very health and life, we must become still 
more extravagant in our condemnatory expressions concerning them. 
We have long looked on mosquitoes, house-flies, and fleas as annoyances 
and even torments, but that each of these pests actually acts as an inter¬ 
mediate host for, and is an active disseminator of, one or more wide-spread 
and fatal diseases is knowledge that has been got only recently. Mosquitoes 
help to propagate, and are, almost certainly, the exclusive disseminating agents 
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