2/6 Alexander Petruukevitch 



one eliter and one leg malformed and showed other minor 

 defects. Upon investigation the male proved to have normal 

 spermatozoa and the female laid an extraordinarily large number 

 of eggs. Similar cases are common among all insects as v^ell as 

 other animals. I have made the same observation in the beetle, 

 Lucanus cervus, the males of which have the beautiful horns on 

 their heads. Of the beautiful moth, Samia cecropia, over a hun- 

 dred of which I allowed to develop in a cage for other experi- 

 ments, many couples with entirely defective and malformed wings 

 were found in coitu. Among orb-w^eaving spiders are several 

 species in which during the mating period the female allows 

 several males to remain in her net, of course at a good distance 

 from her, and it is a common occurrence for defective males to be 

 accepted by the female while perfect ones will be chased away for 

 their dear life or will even fall victims to the voracity of the much 

 stronger female. Protective structure or coloration belongs to 

 the same group of phenomena and here a great number of cases 

 might be recorded where an animal remains entirely unaware of 

 the protection afforded by its form and color if in the proper sur- 

 soundings and of the danger of disregarding this. I have seen 

 butterflies that would be protected by the leaf-like coloration of 

 their wings if they should sit motionless, instantly caught on the 

 wing by large dragonflies, and in the West Indies I could observe 

 regularly a hemipteron of the group Emesidae, which would 

 resemble a dead twig if in an appropriate position, swinging to 

 and fro on the four hind legs in the center of a large leaf. All 

 this I bring here by no means with the object of denying the 

 existence of adaptation or of the principle of selection itself, which 

 only one who has never observed nature outside of the laboratory 

 can do. But I want to show that in all those instances where the 

 animal itself cannot make use of a new variation or mutation, in 

 the possession of which it has been placed by nature, its advanta- 

 geous character will be a mere matter of chance, and selection, if it 

 take place, must be greatly retarded in its progress. 



Quite different must it be with those structures which the animal 

 is able to put to active use, however unconscious it may be of the 

 advantage it enjoys over other individuals of the same species. 



