CHAPTER II 



THE GRASSHOPPER 



The Habits, Physiology, Anatomy, and Economic 

 Relations of a Typical Insect 



About four fifths of the five hundred thousand different kinds 

 of animals known to man belong to a single group which we call 

 insects. Not only are insects numerous, so far as the number of 

 kinds is concerned, but there is an abundance of individuals of 

 each kind. This abundance makes it possible for us to collect 

 them without difficulty, and hence it is easy to obtain material 

 for our studies. Besides this, many insects, such as butterflies 

 and beetles, are very beautiful ; they are also wonderfully adapted 

 to their various habitats, and when collected and properly ar- 

 ranged in a cabinet make one of the most interesting and instruc- 

 tive exhibits of natural objects that it is possible to possess. 

 Furthermore, certain insects, like the honeybee and silkworm, are 

 of great commercial value ; the gipsy moth, potato beetle, chinch 

 bug, army worm, and thousands of others must be continually 

 fought to prevent the destruction of our crops ; and certain kinds, 

 the house fly and mosquito, for instance, are the principal 

 cause of the transmission of diseases like typhoid fever, 

 malarial fever, and yellow fever. 



When we have learned the general structure and functions of 

 the parts of an insect, it is an easy task to distinguish these ani- 

 mals from all others ; and such a study lays the foundation which 

 will help us to understand the activities of other kinds of insects 

 and the structures concerned with these activities. In selecting 

 an insect for this first study we should try to find one large enough 



8 



