70 ELEMENTARY ZOOLOGY 



Examine a male hairy woodpecker and a female ; (in 

 western States substitute a Harris's hairy woodpecker). 

 Note the similarity in markings and structure to the 

 downy. Note the marked difference in size. Make notes 

 of measurements, colors and markings, and drawings of 

 bill and feet, showing the resemblances and the differ- 

 ences between the downy woodpecker and the hairy 

 woodpecker. These two kinds of woodpeckers are very 

 much alike, but the hairy woodpeckers are always much 

 larger (nearly a half) than the downy woodpeckers and 

 the two kinds never mate together. The hairy wood- 

 peckers constitute another species of bird. 



Genus. Examine now a flicker (the yellow-shafted 

 or golden-winged flicker in the East, the red-shafted 

 flicker in the West). Compare it with the downy wood- 

 pecker and the hairy woodpecker. Make notes referring 

 to the differences, also the resemblances. The flicker 

 is very differently marked and colored and is also much 

 larger than the downy woodpecker, but its bill and feet 

 and general make-up are similar and it is obviously a 

 ' * woodpecker. ' ' It is, however, evidently another species 

 of woodpecker, and a species which differs from either the 

 downy or the hairy woodpecker much more than these 

 two species differ from each other. There are two other 

 species of flickers in North America which, although 

 different from the yellow-shafted flicker, yet resemble it 

 much more than they do the downy and hairy wood- 

 peckers or any other woodpeckers. We can obviously 

 make two groups of our woodpeckers so far studied, 

 putting the downy and hairy woodpeckers (together with 

 half a dozen other species very much like them) into one 

 group and the three flickers together into another group. 

 Each of these groups is called a germs, and genus is thus 

 the name of the next group above the species. A genus 

 usually includes several, or if there be such, many, 



