INTROD UCTION. 5 



maggot-like creature wliicli feeds upon the store provided for it, 

 increasing rapidly in size, and entering tlie pupal stage in from 

 three days to two weeks. In the cocoon it passes through its 

 final metamorphosis, emerging as a perfect insect, perhaps in 

 two or three weeks, or, in many cases, after the winter months 

 have passed and summer has come again. Probably no solitary 

 wasp lives through the winter, those that come out in the spring 

 or summer perishing in the autumn. 



The social hymenoptera are born into a community, and their 

 mental processes may be modified and assisted by education and 

 imitation, but the solitary wasp (with rare exceptions) comes 

 into the world absolutely alone. It has no knowledge of its 

 progenitors, which have perished long before, and no relations 

 with others of its kind. It must then depend entirely upon its 

 inherited instincts to determine the form of its activities, and 

 although these instincts are much more flexible than has been 

 generally supposed, and are often modified by individual judg- 

 ment and experience, they are still so complex and remarkable 

 as to offer a wide field for study and speculation. 



