114 THE ANIMALS AND MAN 



Family. — Examine a red-headed woodpecker {Mela- 

 nerpes erythrocephalus) and a sapsucker (Sphyrapicus 

 varius) and any other kinds of woodpeckers which can be 

 got. Find out in what ways the hairy and downy wood- 

 peckers (genus Dry abates), the flickers (genus Colaptes), 

 and the other woodpeckers resemble each other. Examine 

 especially the bill, feet, wings and tail. These birds differ 

 in size, color and markings, but they are obviously all alike 

 in certain important structural respects. We recognize 

 them all as woodpeckers. We can group all the wood- 

 peckers together, including several different genera, to form 

 a group which is called a family. A family is a group of 

 genera which have a considerable number of common struc- 

 tural features. Each family is given a proper name consisting 

 of a single word. The family of woodpeckers is named 

 PicidcB. 



We have already learned that resemblances between 

 animals indicate • (usually) relationship, and that classify- 

 ing animals is simply expressing or indicating these relation- 

 ships. When we group several species together to form 

 a genus we indicate that these species are closely related. 

 And similarly a family is a group of related genera. 



Order. — There are other groups* higher or more com- 

 prehensive than families, but the principle on which they 

 are constituted is exactly the same as that already explained. 

 Thus a number of related families are grouped together to 

 form an order. All the fowl-like birds, including the families 

 of pheasants, turkeys, grouse and quail, all obviously re- 

 lated, constitute the order of gallinaceous birds called 

 Gallina. The families of vultures, hawks and owls con- 

 stitute the order of birds of prey, the Raptores, and the fami- 

 lies of the thrushes, wrens, warblers, sparrows, black-birds, 



*Each of these higher groups has a proper name composed of a single 

 word. In the case of no group except the species is a name-word ever 

 duplicated. Each genus, family, order, or higher group has a name-word 

 peculiar to it, and belonging to it alone, 



