October, '09] JOURNAL OF ECONOMIC ENTOMOLOGY 315 



jump or a gorgeouslj' winged butterfly dance over the meadows. And 

 if we accept the smaller estimate as correct, we have only to reduce 

 the daily working hours to twelve, and allot ten minutes instead of* five 

 for the study of each species to obtain precisely the same result. 

 And yet there are people who are surprised if a professional ento- 

 mologist fails to promptly recognize everj^ specimen submitted to 

 him for identification! The descriptions of about 300,000 insects 

 have been written and published. The uudeseribed forms are, many 

 of them, small, and many inhabit but partially explored regions of 

 the earth, such as the tropics of South America and Africa. 



Fortunate it is for mankind that the insect world is a house divided 

 against itself, otherwise the greenest and most fertile lands in the 

 world would shortly become lifeless deserts. Except for the check 

 put upon insect multiplication through warfare within the insect 

 household, by which one species of insect destroys its relatives, no 

 informed naturalist would expect the survival of the human race for 

 a longer period than five or six years. Not only would man's food 

 supplj" be appropriated by his insect enemies, but it would be impos- 

 sible for him to withstand the withering march of malaria, yellow 

 fever, typhoid, bubonic plague, sleeping sickness and other maladies 

 transmitted through insect carriers, that would consume like a de- 

 vouring fire and leave in their track a desolation compared with 

 which the plagues of Egypt were happy visitations, though these 

 were in part insect outbreaks. The fecundity of insects is amazing. 

 Huxley estimated that a single aphis or plant louse would produce in 

 ten generations, if no mishaps occurred to cut short the natural life 

 of any of her descendants, a mass of organic matter equivalent to the 

 bulk of 500,000,000 human beings or the whole population of the 

 Chinese empire. The common apple plant louse has normally about 

 eight generations in one season, the greater proportion of the indi- 

 viduals failing for various reasons to reproduce, the chief cause of 

 repression of multiplication being the work of insect parasites and 

 predaceous insect forms, which for so long a time and with such cer- 

 tainty of result have transformed a potential peril into a well-bal- 

 anced condition of safety that we give but scant attention to the 

 aphids, and only occasionally find it advisable to turn on them our 

 batteries of insecticides, to do clumsily and expensively what nature 

 does without noise or change from her customary processes. 



Insects render themselves obnoxious to man in two ways: First, 

 by partially or wholty destroying his crops and harming his domestic- 

 ated animals ; and second, by attacking him directly, either inflicting 

 pain upon him or inoculating him with disease, some forms of which 



