94 THE MEANING OF EVOLUTION 



an interesting variation of conditions to which it must 

 adapt itself. The means by which it accomphshes this 

 will be clearer if the mouth of the grasshopper be 

 compared with our own. Our lips are upper and 

 lower, but the grasshopper has a front lip and a hind 

 one. The broad front lip is easily seen at the for- 

 ward side of the mouth. Just behind it, serving the 

 purpose of our teeth, is a pair of hard jaws with 

 horny tips upon them, which serve to break small 

 pieces from its food. While our jaws and those of all 

 other backboned animals work up and down, so that 

 we may be said to have an upper and lower jaw, the 

 grasshopper and all of his insect, crab, or spider re- 

 lations, which have jaws at all, have them right and 

 left, and they work from side to side. Behind these 

 harder mouth parts is found a pair of softer jaws, 

 each of which has on it a little finger-like feeler. 

 With this pair the insect holds its food while the hard 

 jaws break it to pieces. The hind lip follows, and is 

 also provided with short finger-like feelers. The feel- 

 ers on the hind lip and on the soft jaw are necessary 

 because the eyes are so placed as not to be able to see 

 what goes into the mouth, hence the insect must make 

 up for the loss of sight by the addition of touch. The 

 same type of mouth as the grasshopper has will be 

 found among the beetles. Here the males sometimes 

 have the hard jaws so enormously enlarged that they 



