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The animals so excelling succeed in life and subsequently abound 

 in numbers. It is putting the cart before the horse to attribute 

 their success to their abundance . What is required is qualification, 

 first and last. 



The same holds good of the case of the fertilisation of flowers 

 by birds. 



Each part of the globe (says Wallace), has special groups of birds 

 which are flower-haunters. America has the humming-birds (Trochilidae) 

 and the smaller group of the sugar-birds (Caerebidae). In the Eastern 

 tropics the sun-birds (Nectarineidae) take the place of the humming-birds, 

 and another small group, the flower-peckers (Dicaeidae), assist them. 

 In the Australian region there are also two flower-feeding groups, 

 the meliphagidae, or honey-suckers, and the brush-tongued lories 

 (Trichoglossidae) . 



(Again), the great extent to which insect and bird agency is necessary 

 to flowers is well shown by the case of New Zealand. The entire country 

 is comparatively poor in species of insects, especially in bees and butter- 

 flies which are the chief flower fertilisers ; yet according to the researches 

 of local botanists no less than one-fourth of all the flowering plants are 

 incapable of self -fertilisation, and, therefore, wholly dependent on insect 

 or bird agency for the continuance of the species. 



All of which testifies to the vast and important role played in 

 the world of life by cross-feeding animal " specialists." Although 

 in sheer numbers the robbers and parasites may exceed, yet it 

 is the armies of the workers which support and primarily determine 

 evolution. On the score of the inferiority of self -fertilisation, 

 Dr. Wallace tells us : 



An immense variety of plants are habitually self -fertilised, and their 

 numbers probably far exceed those which are habitually cross-fertilised 

 by insects. Almost all the very small or obscure flowered plants with 

 hermaphrodite flowers are of this kind. Most of these, however, may be 

 insect fertilised occasionally, and may, therefore, come under the rule 

 that no species are perpetually self-fertilised. It is now believed by some 

 botanists that many inconspicuous and imperfect flowers, including 

 those that are wind-fertilised, such as plantains, nettles, sedges, and grasses, 

 do not represent primitive or undeveloped forms, but are degradations 

 from more perfect flowers which were once adapted to insect fertilisation. 

 In almost every order we find some plants which have become thus 

 reduced or degraded for wind or self-fertilisation. 



Again, speaking of the " Dispersal of Plants," in another 

 place, Wallace states : 



It is a very suggestive fact, that all the trees and shrubs in the Azores 

 bear berries or small fruits which are eaten by birds ; while all those which 

 bear larger fruits, or are eaten chiefly by mammals such as oaks, beeches, 

 hazels, crabs, etc., are entirely wanting. 



