142 THE MEANING OF EVOLUTION 
When the katydids arrive their jaws are young and 
tender, but so are the leaves upon which they are born. 
Hence there is little difficulty on the part of the young 
katydids in finding an abundance of food. By the 
time the leaves have grown tougher, the katydid’s 
jaws are stronger, and the leaves will still serve as 
food. 
Everyone who is at all familiar with country life 
and gardening is familiar with what is called the po- 
tato or tomato worm. It is a long, green, smooth, 
caterpillar, as long and as fat as your finger and pro- 
vided with a horn upon his tail. The gardener may 
not know that after a while this creature will burrow 
into the ground, and there change into an oblong 
brown mass with a sort of a pitcher handle at one 
side. Next year this pupa will split down the back, 
and from out of the brown case will come a hawk- 
moth, which soon will fly with rapidly quivering wings 
and feast upon the nectar of our moon flowers or on 
that of the “Jimson” weed. Those who have cleaned 
these pests from the potato or tomato vines will often 
have noticed one of them covered with what look al- 
most like grains of rice. This appearance reveals an 
interesting story. Some time earlier an insect that 
looked very much like a dainty wasp with a rather 
long sting in its tail hovered over the caterpillar. This 
is the ichneumon fly. Eventually lighting upon the 
