38 ARTHROPODS 



(4) Since these animals are different in all these char- 

 acteristics we separate them into groups called families. 

 This enables us to refer to them more definitely. The grass- 

 hopper belongs to the family Acrididae, the cricket to the 

 family Gryllidae, the locust to the Locustidae, and the mantis 

 to MafUidae. These names may be put into the diagram to 

 the right of the double line. The names of families usually 

 end in dae. 



(5) The grasshopper, we have found, belongs to the 

 order Orthoptera and the family Acrididae, but since there 

 are a great many kinds of grasshoppers we are not yet able 

 to refer definitely to any one kind. Therefore a further 

 classification is necessary. We divide the family into genera 

 and the genera into species. Thus the grasshopper we stu- 

 died belongs to the genus Melanoplus and to the species dif- 

 fer entialis ; the cricket belongs to the genus Gryllus, species 

 domesticus, etc. When we use Melanoplus differentialis we 

 refer to a species of grasshopper all of the individuals of 

 which are alike wherever they may be found. 



(6) If we wish to locate a person where others may be 

 able to find him, we must give his country, state, county, 

 city, street, number on street and name ; likewise if we wish 

 to classify an animal so that one may locate it, we must give 

 its kingdom, branch, class, order, family, genus and species 



So we see that finding the names of animals is somewhat 

 like finding people. 



(7) The order Orthoptera comprises six common fam- 

 ilies : 



Acrididae, or grasshoppers. 

 GrylHdae, or crickets. 

 Blattidae, or roaches. 



