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EVOLUTION AND ANIMAL LIFE 



Collect a few thousand individuals, at one time in one place, 

 of a single species of insect, as a spotted ladybird beetle; then 

 go over these carefully, looking for variation in some single 

 characteristic, as the color pattern. What do you find? Let us 



F'-G. 72. — Diagram showing variation in elytral pattern of the convergent ladybird, 

 Hippodamia convergens : 1, Mode; 2-9, variations in size of spots; 10-17, variations 

 by coalescence of spots; 18-40. variations by reduction in number of spots. (After 

 Kellogg and Bell./ 



