CHAPTER XVIII 

 INSECTS AND DISEASE 



I HROUGHOUT this book reference is constantly 

 made to the injuries done by insects to our 

 forest-trees, fiowers, fruits, vegetables, and 

 grains. The millions of dollars lost annually 

 because of the sap-sucking of the San Josd 

 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 coUected by agents with two feet instead 

 of being levied by Nature and collected by si.x-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. 



\Mien 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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