88 GENERAL ZOOLOGY 



of the actions of animals should not be classified as purely 

 instinctive or purely intelligent, for they may contain elements 

 of both factors. The words " instinctive " and " intelligent " 

 can only be used to denote an apparent preponderance of one 

 or the other factor. This is well illustrated by the observa- 

 tion Professor Morgan quotes from M. Fabre, who " describes 

 how a Sphex, one of the solitary wasps, instinctively draws its 

 prey, a grasshopper, into the burrow by its antennae. When 

 these were cut off the wasp pulled the grasshopper in by the 

 jaw appendages ; but when these were removed she seemed 

 incapable of further accommodation to the unusual circum- 

 stances." Here we see not only obedience to a strongly 

 marked instinctive tendency, but also some power to modify 

 the instinctive reaction. It seems strange to us that if the 

 wasp were capable of making this deviation from her instinc- 

 tive mode of procedure, she should not take the slight further 

 step of seizing upon the fore legs. 



Another caution must also be stated. The distinctions 

 already made assume that we are able to determine the 

 mental states of animals ; but this is true only in a very gen- 

 eral way. We interpret the mental state of human beings 

 by inference from their actions, but with the lower animals 

 we have no positive means of knowing what mental state 

 accompanies any given action, since their physical organiza- 

 tion is so different from ours. And not only is this true, but 

 we also lack a language to express the facts we observe con- 

 cerning the mental life of the lower animals, since the words 

 we use have their meaning in connection with the facts of 

 human psychology. 



Economic Importance of Insects. According to the report 

 of the Secretary of Agriculture for 1902, the fixed capital of 

 agriculture in the United States amounted in 1900 to twenty 

 billions of dollars, or four times the amount invested in 

 manufactures. More than half of the people of the United 



