132 Instinct. 



them their whole value in securing the welfare of 

 their possessor. 



Among spiders w^e find, perhaps, the best il- 

 lustrations of the great diversity of the results pro- 

 duced by the joint action of these three agencies, 

 in animals very nearly allied. A whole lecture 

 might be given in showing the varied uses to which 

 different species of spiders put this web-making se- 

 cretion which is common to nearly the whole spider 

 tribe. We have webs of a multitude of forms — 

 fine threads, as treacherous snares — curious nests 

 lined with satin, and homes beneath the water ; be- 

 sides sacks and covers, from the thinness of gauze 

 to the thickness of paper, to protect their eggs and 

 young. The problem does not seem to be ; In how 

 few ways can Instinct avail itself of function to pro- 

 vide for the family of spiders ? but rather. In how 

 great a multiplicity of methods ? — as though diver- 

 sity were the object aimed at ; and yet each meth- 

 od would challenge our admiration, if all spiders in 

 the world were found using that alone. 



In this connection we cannot fail to notice the 

 relation of Instinct to form and color. 



It is well known that many wild animals corres- 

 pond in color very closely to the coloring of the 

 earth and herbage where they live. Among the 

 higher animals, especially among birds, every care- 

 ful observer has noticed that many of them seek 

 those places where their colors will best harmonize 

 with the surrounding objects. The Grouse, already 

 referred to, so closely resembles in color the with- 



