FOR THE FIELD AND FIELD TRIALS. 4! 



cording to a preconcerted plan. They capture slaves. 

 They move the eggs of their aphides, as well as their 

 own eggs and cocoons, into warm parts of the nest, 

 in order that they may be quickly hatched, and end- 

 less similar facts could be given. On the whole, the 

 difference between the mental powers of an ant and a 

 coccus is immense ; yet no one has ever dreamed of 

 placing these insects in distinct classes, much less in 

 distinct kingdoms. No doubt the difference is 

 bridged over by other insects; and this is not the 

 case with man and the higher apes. But we have 

 every reason to believe that the breaks in the series 

 are simply the result of many forms having become 

 extinct." 



These extracts, given for the reader's considera- 

 tion, present the convictions of men who have made 

 this and related subjects a lifelong study, whose 

 opportunities for acquiring information were rela- 

 tively unlimited and whose mental equipment fitted 

 peculiarly well to the exactions of their chosen field 

 of research, all of which qualified them for the mak- 

 ing of sound conclusions. 



There is a comprehensive literature on this sub- 

 ject, extremely interesting in itself. It is only in- 



