64 ANIMAL BIOLOGY 



ments represent the culmination of a long life of evolution 

 from the solitary species. 



In the wasps, as in the bees, there are both solitary and 

 social species. The solitary wasps commonly prey upon 

 insects and spiders which they store in their nests as 

 provision for their young larvae. The habits of a number 

 of species have been carefully studied by Dr. and Mrs. 



FIG. 55. Solitary wasp, Ammophila, stinging a caterpillar. (After 



Peckham.) 



Peckham who have written a most interesting book upon 

 the results of their investigations. Each species generally 

 hunts a particular kind of prey and constructs a particu- 

 lar kind of nest. In many cases the prey is stung so as 

 to paralyze it without destroying its life, thus providing 

 the larvae with a supply of fresh food. The digger 

 wasp Psammophila makes a little hole in the earth, and 

 then goes in search of a caterpillar which it proceeds to 

 sting on the ventral side of the body near the nerve cen- 

 ters. Then the wasp flies across the fields with her bur- 



