1 34 Instinct. 



in the axil of a leaf, just where a bud would be 

 found. 



But every observer of our own insects has seen 

 among them examples of this correlation of In- 

 stinct with form and color. Some of our caterpil- 

 lars have the color and form of short sticks. They, 

 in case of danger, fasten themselves upon a limb 

 and extend the body so that men and birds are 

 both deceived ; so completely do color, form and 

 position mimic a dry stub upon the bush. The cu- 

 rious thing is, no matter now how it has been se- 

 cured, that Instinct should come in among butter- 

 flies, spiders, caterpillars and hosts of other animals 

 to complete the work of deception, which is begun 

 by color and form, simulating the common appear- 

 ance of leaves in all their changes and flowers and 

 buds and sticks. 



In every step that we have taken in this investi- 

 gation, we have found Instinct becoming a part of 

 a more complex system of agencies, but still filling 

 a place which function of organs alone could not 

 possibly fill — securing results that might be obtain- 

 ed through experience and instruction by some an- 

 imals if there were any way to provide for the con- 

 tinuance of the race of animals until experience 

 could be gained. But in the case of those animals 

 that could possibly learn by experience, something 

 must go before it. There must be impulse and so 

 much of guidance as to preserve the animal till ex- 

 perience can come to his rescue. But with many 

 animals knowledge from experience is impossible, 



