1 64 THE ATTRACTIONS OF ENTOMOLOGY 



propagated by these parasites; and it is only by carefully 

 working out all the different life stories and habits of these 

 deadly pests that we are gradually gaining knowledge which, 

 if systematically and intelligently applied, will enable us to 

 stamp out these fell scourges. As an illustration of these 

 statements may be mentioned the fact that the first attempt 

 to construct the Panama Canal failed, owing largely to the 

 decimation by malaria and yellow fever, of those who were 

 engaged in the work. At that time it was not known that 

 these diseases were caused by the bite of two different kinds 

 of infected mosquito, but when this fact had been ascer- 

 tained, and the breeding habits of these special varieties had 

 been thorouhly investigated, it became possible to equip an 

 effective anti-mosquito brigade whose work enabled the 

 gigantic undertaking to be completed without further hind- 

 rance from this cause. Again, the simple fact that fleas 

 desert the corpses of plague-infected rats and carry the 

 disease to human beings, has enabled intelligent measures to 

 be adopted, whereby Europe has been protected from this 

 deadly scourage, although Asia has been terribly and ex- 

 tensively ravaged by it for the last quarter of a century, and 

 the two continents are closely associated both geographically 

 and commercially. Many other instances might be given of 

 the part played by insects in propagating human diseases, 

 and of the scientific triumphs achieved by the judicious 

 application of measures directed against these infection 

 carriers, but enough has been said to show how essential to 

 man's very existence is the study of this branch of natural 

 history. 



How is it then that this subject is very generally 

 neglected notwithstanding that it is so attractive to every 

 healthy minded child, is inexhaustibly full of strange and 

 wonderful beauty, is replete with material for abstract 

 thought, and at the same time is of such immense practical 

 importance to man's welfare? There appear to be two rea- 

 sons for this regrettable lack of popular interest. In the first 

 place entomologists in the past have largely concentrated 

 their attention on the mere outward form and structure of 

 insects, and have constructed very elaborate and complicated 

 systems of classification based on the number of hairs, or 

 bristles, or scales possessed by closely related insects, the 

 slightest variation being deemed sufficient justification for 

 labelling a specimen with some distinctive, outlandish name. 

 Very often, further study sho'ws the creature to possess an 

 overlooked hair or some undetected remnant of an organ 

 entitling it to be put into another class with a new name; 

 or two observers may have described the same insect in- 



