OUR FIGHT AGAINST INSECTS 191 



come into the insects' view, and they eat the poles and 

 even burrow into the insulating lead of the wire coils. 

 A still later step in man's advance, the airplane, also in- 

 volves a fight against the insects, for the wood which is 

 used in their propellers is also damaged by certain 

 species. 



Most domestic animals suffer greatly from their at- 

 tacks. Almost every kind of animal that is domesti- 

 cated and used by human beings has its serious insect 

 enemies, and man himself is far from immune. Aside 

 from the species that sting him and annoy him, there 

 are other forms that carry disease. The house fly 

 carries at least thirty different kinds of disease and 

 parasites. Mosquitoes of different kinds are responsible 

 for distribution of malaria and yellow fever, dengue 

 /ever, and filariasis. The tsetse fly carries the sleeping 

 sickness which has decimated large areas in Africa, the 

 tick carries the germs of Rocky Mountain fever, and 

 there are many other insects that carry various dis- 

 eases, some doubtless unknown. 



A few years ago we should have said that this was a 

 fairly comprehensive summary of the possibilities of in- 

 sect damage, but it has recently been discovered that 

 they are responsible for the carriage of many of the most 

 fatal diseases of cultivated plants just as they carry 

 the diseases of animals and man. They are carriers of 

 fatal diseases to many of the most important crops and 

 to fight the diseases we must fight the insect carriers and 

 control them. 



Country after country has organized its entomo- 

 logical service, following the lead of the United States* 



