136 



EVOLUTION AND ANIMAL LIFE 



tion, number of wing hooks, etc., in two dozen different insect 

 species. Long ago Dr. J. A. Allen, of the American Museum of 

 Natural History, gave similar data of the actual variation in 



FIG. 78. Red-legged locust, Melanoplus FIG. 79. The seventeen-year locust, Cicada 



femur-rubrum, and hind tibia, showing septendecim, and its hind tibia, showing 



inner and outer rows of spines. (After inner and outer spines. (After Kellogg 



Kellogg and Bell.) and Bell.) 



various familiar American bird species, his data referring 

 chiefly to variations in dimensions; as length of whole body, 

 length of tail, of wing, of bill, of tarsus and claw, etc. 



CARDINALIS V/ftG/WANUS 58 specimens, Florida. 



Tail. 



Length of Bird 



Winy. 



V.Vo 









 >< 







FIG. 80. Diagram showing variation in length of tail, body, and wing in fifty-eight 

 specimens of the card'^al, Cardinalis (formerly called virginianus), from Florida. 

 (After Allen.) 



And anyone with means of collecting considerable series of 

 individuals of single species can, if he but give the time and 

 study to it, reveal similar variations in almost any part or 

 characteristic of any species or kind of plant or animal. " What 



