INSECTS AND MAN 



mology, that the credit must be given for breaking down 

 the barrier of prejudice. Their brilliant researches into 

 the part played by insects in the spread of disease have 

 appealed more strongly to the popular imagination than 

 equally important discoveries in the domain of agricultural 

 entomology. There is work to be done in the agricultural 

 field every whit as important and far-reaching as anything 

 that has been accomplished on the medical side. Insects, 

 adapted to every climatic and topographical condition of the 

 world, have developed into an incredible number of species 

 ten million it is said, and, excepting microscopical 

 plants and animals, they far outnumber all the other living 

 beings put together. 



It is fortunate for man that the insect world is a house 

 divided against itself ; except for this check the human race 

 would be extinct in five or six years. The fecundity of many 

 insects is enormous ; Huxley estimated that, mishaps apart, 

 a single green fly would, in ten generations, produce a mass 

 of organic matter equivalent to five hundred million human 

 beings, or as many as the whole population of the Chinese 

 Empire. From the earliest times man has suffered from 

 insect damage to his crops, his livestock, and himself. 

 Locust plagues, rivalling those of Egypt, have come to 

 man from time to time. Pliny mentions them ; they visited 

 Ukraine in 1645, and America at the close of the civil war ; 

 a vast swarm two thousand miles in extent crossed the 

 Red Sea in 1889, and eight years previously one thousand 

 three hundred tons of locust eggs were destroyed in Cyprus 

 alone. But this is not all ; the United States suffers damage 

 annually to the extent of $40,000,000 owing to the depre- 

 dations of the Hessian fly; the cotton-boll weevil causes 

 an annual loss of $30,000,000 ; the codling moth $15,000,000, 

 and the chinch bug $7,000,000; add to this the damage 

 done by gipsy and brown-tail moths, and the San Jose' 

 scale, to say nothing of a host of minor pests, and the 

 total assumes alarming proportions. Turning to our own 



