THE ATTRACTIONS OF ENTOMOLOGY 163 



amongst the simplest forms of insect life. 1 Again, persons 

 attracted by biological questions connected with the origin 

 and development of life on the earth, find much food for 

 abstract thought in observing the springs of life actually at 

 work in the transparent tissues of some of these perfectly 

 constructed creatures; in following out their strangely com- 

 plicated metamorphosis ; in noting their wonderful adaptation 

 to environment and fierce struggle for existence ensuring the 

 survival of the fittest; in the amazing intelligence revealed 

 by their social life, and in their altogether inexplicable powers 

 of instinct : — Surely then we should also obtain inspiration 

 in insects, if we can find 



"Tongues in trees, books in the running brooks 

 Sermons in stones and good in everything." 



More practical minds, however, care for none of these 

 things and demand impatiently whether the study of these 

 low forms of life has any direct bearing on human affairs, or 

 serves any directly useful purpose in every day life. The 

 astonishing and far reaching practical results obtained by the 

 study of entomology during the last quarter of a century 

 warrant a very decisive affirmative reply to these questions. 

 For a long time past it has been known that insects were 

 essential agents in the fertilization of plants, as well as in 

 scavenging all the dead, useless, putrefactive matter that 

 would otherwise render the earth unfit for habitation, — thus 

 playing a twofold beneficial role in the economy of Nature. 

 But, as so frequently happens in this world, evil is inextric- 

 ably associated with good in both these processes, and quite 

 recently, serious attention has been drawn to the ravages 

 committed by insects on the fruits, cereals and vegetables 

 that form such a large part of the world's food supply, and on 

 many other plants necessary for various industrial purposes. 

 So large have been the losses sustained from these causes 

 that many civilised countries find it advisable to maintain 

 experimental stations where the life histories of these pests 

 are carefully investigated with a view to preventing their 

 growth and development, for it is chiefly in the larval or 

 caterpillar stage that such insects exert their most injurious 

 effects on plants. But although vast quantities of valuable 

 food material are saved every year through the study of what 

 may be called agricultural entomology, yet this represents 

 only a small fraction of the total practical results obtained 

 from applying our knowledge of the life history of insects. 

 For whilst the larvae are such potent factors in destroying 

 useful forms of vegetable life, the full-grown insects have 

 been found to be equally dangerous to animals, the human 

 race in particular suffering terribly from various diseases 



