ADAPTATION FOR THE SPECIES I4I 



game. It is the fittest that survive. When this pro- 

 cedure goes on generation after generation, the result 

 must necessarily be that the spiders grow fitter and 

 fitter for their work. This method is hard on the 

 little spider, but it makes good spiders. 



Most insects die before their eggs hatch; accord- 

 ingly they can pay no attention to their own children. 

 Whatever arrangements are provided for the safety 

 and strength of these offspring must be provided be- 

 fore they appear. About the only care the majority 

 of insects take in this direction is to see that the eggs 

 are placed where the young shall find food as soon 

 as they emerge. Insects' eggs are very small, and as 

 a consequence the creatures which emerge from them 

 are likewise exceedingly minute. As a result they 

 cannot be expected to hunt far for their food. Differ- 

 ent insects use different devices by which to overcome 

 this difficulty. The katydid, for Instance, must die 

 with the approach of fall. Her children will not ap- 

 pear until the following year. Her food consists of 

 leaves, but to lay the eggs in such a situation would 

 be a fatal process, because the leaf will drop off 

 before the eggs hatch. Accordingly, the katydid lays 

 its shield-shaped eggs in a double row near the end of 

 a young twig. Next year when the weather is suffi- 

 ciently warm to hatch katydids, it is also warm 

 enough to force the buds on the end of the twigs. 



