ii DEVELOPMENT OF ANIMAL LIFE 141 



superior species. Such is the human species, which 

 represents the culminating point of the evolution of the 

 vertebrates. But such also are, in the series of the 

 articulate, the insects and in particular certain Hymen- 

 optera. It has been said of the ants that, as man is 

 lord of the soil, they are lords of the sub-soil. 



On the other hand, a group of species that has 

 appeared late may be a group of degenerates ; but, for 

 that, some special cause of retrogression must have 

 intervened. By right, this group should be superior 

 to the group from which it is derived, since it would 

 correspond to a more advanced stage of evolution. 

 Now man is probably the latest comer of the verte 

 brates ; 1 and in the insect series no species is later than 

 the Hymenoptera, unless it be the Lepidoptera, which 

 are probably degenerates, living parasitically on flower 

 ing plants. 



So, by different ways, we are led to the same con 

 clusion. The evolution of the arthropods reaches its 

 culminating point in the insect, and in particular in 

 the Hymenoptera, as that of the vertebrates in man. 

 Now, since instinct is nowhere so developed as in the 

 insect world, and in no group of insects so marvel 

 lously as in the Hymenoptera, it may be said that the 

 whole evolution of the animal kingdom, apart from 

 retrogressions towards vegetative life, has taken place 

 on two divergent paths, one of which led to instinct 

 and the other to intelligence. 



1 This point is disputed by M. Rene&quot; Quinton, who regards the car 

 nivorous and ruminant mammals, as well as certain birds, as subsequent 

 to man (R. Quinton, L Eau de mer milieu organique, Paris, 1904, p. 435). 

 We may say here that our general conclusions, although very different from 

 M. Quinton s, are not irreconcilable with them ; for if evolution has really 

 been such as we represent it, the vertebrates must have made an effort 

 to maintain themselves in the most favourable conditions of activity 

 the very conditions, indeed, which life had chosen in the beginning. 



