INSECTS AND MANKIND 445 



have seen how the harmful effects wrought by insects often 

 follow inevitably from human activity in cultivation and 

 domestication, and how these effects have themselves 

 stimulated man to inquiry and thus to the attainment of 

 knowledge through which preventive and remedial measures 

 have been indicated. And thus we realise that there was 

 justification for the hopeful vision of Joel, who, using the 

 destructive locust-swarms of the Mediterranean coast- 

 lands as symbols of ravaging armies, recognised them as 

 working out ultimately a beneficent purpose, and held to 

 the faith that '* the years which the locust and the caterpillar 

 had eaten " should be in due time restored. 



Many insects are, as we have seen, definitely serviceable 

 to man, by acting as scavengers, by preying on the destroyers 

 of crops, and by furnishing useful products such as honey 

 and silk. The most valuable contribution, however, which 

 insects as a class have made to the w^ell-being and enjoyment 

 of mankind, is undoubtedly to be seen in the result of their 

 association with the higher seed-plants, apparent in the 

 colour and scent of flowers, and the development of the 

 fruits of plants dependent for pollination on insect visitors. 

 The world into which man came would have been far less 

 attractive and sustaining than he found it, but for the inter- 

 actions which had gone on between the higher insects and 

 the plants through the later Secondary and the Tertiary 

 eras of geological histor}^ 



Yet beyond these considerations insects have been a 

 means of benefit to man through their direct appeal to his 

 love of beauty and his search for truth. The student of 

 these creatures finds beauty not only in the brilliant hues 

 of a butterfly's wing or the metallic sheen of a beetle's 

 elytron, but also in the wonderfully adapted form of those 

 minute organs and structures which subserve the needs of 

 life ; graceful feathered feelers that are the seat of delicate 

 sense-organs, claws and pads on feet that ensure firm hold 

 in walking — all might well be acclaimed as *' miracles of 

 design." We have seen how the study of insect structure 

 and development has thrown light on the problems of 



V... 

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