138 INSECT BEHAVIOR 



ent species of the same group of insects, which were recently observed 

 at close range by the author. These experiments are well worthy 

 of note, from the fact that a vast contrast in adaptability was discov- 

 ered between two insect species, so entirely identical in their anatomi- 

 cal structure and so closely related in their classification that they 

 should have been equal to each other, even under the unusual cir- 

 cumstances in which they were placed. Yet in one of these experi- 

 ments it was shown that a certain species possessed the power of in- 

 stantly distinguishing between right and wrong, while the other made 

 plain its inability to leave the beaten path of innate propensity. 



As I have said, the insects in question were both species of wasps; 

 one the common paper wasp x and the other the common blue mud- 

 dauber. 2 



Although they are much alike in structure, their habits are quite 

 at variance, as we shall presently see. 



The paper wasps are a social species; that is, they live in a colony, 

 with a common den, which in this case consists of a group of paper 

 tubes for cells suspended by a central stem from the undersides of 

 overhanging stones or more often from old beams and timbers in 

 barns or sheds. The paper for the nest is manufactured by the wasps 

 from wood pulp, which is scraped from unpainted lumber and then 

 mixed with a glutinous substance, which the insects possess. A large 

 nest will contain in the neighborhood of three hundred cells, but the 

 great majority are complete when one hundred have been constructed. 

 In each of these cells an egg is laid by the queen and the young are 

 fed by the other members of the colony until their period of help- 

 lessness is at an end. Their food consists of chewed up spiders and 

 other insects, mixed with a certain amount of nectar, and is un- 

 doubtedly good. Thus it will be seen that the paper wasps are of a 



1 Polistes. 



2 Chalybion caeruleum. 



