1894. NEUTER INSECTS AND LAMARCKISM . 97 



very properly infer that Natural Selection has been the determining 

 cause of such evolution. 



Neuter castes are confined to a few closely-related families of the 

 social Hymenoptera, and to the termites, or " white ants," as they 

 are popularly called. Seeing how exceptional the peculiarity of this 

 complication is in nature, and yet how extensively it is diffused 

 among the many species of these social insects, we may reasonably 

 conclude that the peculiarity did not arise independently and 

 separately in thousands of species of ants, bees, and wasps, even if 

 it should have had a distinct origin in the case of the termites. 

 Originating, as we may suppose, in exceedingly remote ages, and 

 forming an advantageous basis or accompaniment of social forms of 

 evolution, the peculiarity or susceptibility has been evolved and 

 utilised to an extent which has allowed special scope for many 

 important differences and complexities which otherwise could not 

 have arisen. In some cases, as with some humble bees, comparativelj- 

 solitary conditions, and widely-scattered nests or cells, may have aided 

 or allowed survival, by the more effectual preservation of the honey 

 and larvae from marauding enemies. In such cases. Natural Selection 

 may neglect or repress the social tendency and the intimately-related 

 potentialities and instincts involved in the production of a neuter 

 caste. Wasps, being carnivorous, and, therefore, unable to store and 

 preserve food for the winter, have not evolved so thorough a division 

 of labour and function as the hive-bees ; for such solitary fertilised 

 queens as survive the winter have to house and feed their first brood 

 of neuters by their own efforts. Bees, ants, and termites commonly 

 avoid this annual destruction of the community, their food being 

 less perishable, so that stores can be laid up for times of scarcity. 

 We find that intelligence, instinct, and special structures are 

 most highly elaborated in the neuters of those species in which 

 the queens and drones have most thoroughly lost such capacities or 

 structures. The whole circumstances tend to show that Natural 

 Selection has simultaneously effected increasing specialisation in 

 neuters and queens alike in the direction of division of labour and the 

 more perfect adaptation of each caste to its own particular functions 

 in the community. The various neuter castes seem only to have 

 been evolved in directions that have adequately aided the 

 prosperity of the stirp ; and the continued evolution or improvement 

 of workers, warriors, and other neuters would promote the success of 

 the stock quite independently of any similar development in queens 

 or drones in whom it would be disadvantageous. There seems to be 

 every reason for believing, with Darwin, that complex evolution has 

 taken place in neuter insects, and that the case for the supposed 

 necessity of use-inheritance in such evolution falls to the ground. 



Wm. Platt Ball. 



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