INSECTS 



defense. A pair of slender tubes, the cornicles, projecting 

 from the rear end of the body, eject a sticky liquid which 

 the aphids are said to smear on the faces of attacking 

 insects; but the ruse at best probably does not give much 

 protection. Parthenogenesis and large families are the 

 principal policies by which the aphids insure their race 

 against extinction. 



The presence of "evil" in the world has always been a 

 thorn for those who would preserve their faith in the idea 

 of beneficence in nature. The irritation, however, is not 



Fig. 103. The aphis-lion, feeding on an aphis held in its jaws 



in the flesh but in a distorted growth of the mind, and 

 consequently may be alleviated by a change of mental 

 attitude. The thorn itself, however, is real and can not 

 be explained away. Beneficence is not a part of the 

 scheme by which plants and animals have attained 

 through evolution their present conditions and relations. 

 On the other hand, there are not good species and bad 

 species; for every creature, including ourselves, is a thorn 

 to some other, since each attacks a weaker that may 

 contribute to its existence. There are many insects that 

 destroy the aphids, but these are "enemies" of the aphids 

 only in the sense that we are enemies of chickens and of 

 cabbages, or of any other thing we kill for food or other 

 purposes. 



[174] 



