Reply to Mr Wallace's Theory of Birds' Nests 145 



that the bright colour of flowers is confined to those which require 

 insects to fecundate them, and that the object of their being pro- 

 vided with gay colours is to attract the attention of insects to them. 

 Now, both of these assumptions are without wan-ant. As to the first, 

 many bright flowers in the garden need no insects to fecundate 

 them. For example, what colours can be brighter or more gaudy 

 than those of our orange and tiger lilies, the campanulas, the poppies; 

 almost every gay flower, indeed, which has a long flexible stalk, 

 that will bend with the wind, fecundates itself without help of 

 insects. The stalk and the wind do it between them. As to the 

 second assumption, that the gayness of the colour attracts insects, 

 we have only to observe that insects are provided with very imper- 

 fect and inferior means of vision. They have the power of smell 

 very largely developed, but that of sight is very feeble. What is 

 more, the defect is chiefly in the distance to which they can see ; 

 they are very near-sighted, as any one can convince himself, by 

 watching a butterfly attempting to fly over a high wall. In ap- 

 proaching it, it obviously does not see it until it is close upon it; 

 it retreats a little, and flies a little higher up and again approaches 

 it : again finds the barrier, again repeats the process, and it is only 

 after several attempts that it at last surmounts it. This defect is 

 inherent in the structure of the insect's eye ; and therefore any 

 argument founded upon the analogy of our own vision would lead 

 us wrong ; and it is plain that if the insects cannot see the gay 

 flowers, their bright colour cannot answer the purpose of attract- 

 ing them. 



For the above reasons, we cannot agree with Mr Wallace in the 

 views he has arrived at ; and we have been the more disposed to 

 canvass them, because any hypothesis proposed by him deserves 

 full consideration, not only from the ability with which it is sure to 

 be advocated, but from the weight attached to whatever proceeds 

 from his pen. If his views are erroneous, 'it is of the more import- 

 ance that they should be questioned ; if they are doubtful, that 

 they should be sifted ; and if correct, ventilation will make them 

 only better known. 



