CHAPTER VII 



How Insects are Classified 



More than 350,000 distinct species of insects have been described. 



In addition at least as many more remain to be studied and classified. 



Obviously, in all this array, there must be certain groups that have 



many characters in 

 common, or give 

 indication that at 

 some period in the 

 remote past they 

 were derived from 

 common ancestors. 

 These groups are 

 known as Orders. 



There are more 

 than twenty recog- 

 nized orders of in- 

 sects, but the great 

 majority of injurious 

 species are included 

 in ten principal eco- 

 nomic orders. The 

 leading characteris- 

 tics distinguishing 

 these from one an- 

 other are the type of metamorphosis, the kind of mouth parts, the 

 number, shape, and texture of the wings, the presence or absence 

 of compound eyes, the type of antennae, and the shape of the body. 

 The ten principal orders and their characteristics are as follows: 



22 



Fig. 18. — A typical specimen of the order Orthop- 

 tera. Original. 



