333 The Mechanism of Evolution in Leptinotarsa 



was characterized by the absence of the factors in the make-up of the population 

 that produced biotypes 1, 2, 3, 10, 11, and 12, and these were not present in the 

 introduced group and did not appear during the test, whereas in the test of the 



11- 

 9 m^ 11- 



31 <m agL 11 22 -m^ fl»— -12 



-11 



42 ^ ^_ 7 39 ^ ^■ 



•26 



^. 86 



77 



—-45 



/m m- 42 / / / 



/ \ / / / ^ \ 



1 4 4 11 78. 



Population 256, First Generation. Population 253, Second Generation. 



Fig. 153. — Census showing conditions in the first and second generations in 

 1906 at Chalcicomula test colony. 



17 m> 14- 



47 



31 -^ ^ 9 41 -^ ^p-.__..46 



131 ^ m> mr 78 



^ m- 74 



/ 



^ 12 / / 



---4 



<^^-17 



1 2 9 10 4 6 



Population 294, First Generation. Population 267, Second Generation. 



Fig. 154. — Census showing conditions in first and second generations in 1907 

 at Chalcicomula test colony. 



Fig. 155. — Census showing conditions in first and second generations in 1908 

 at Chalcicomula test colony. 



Chapultepec location under the same conditions all of the biotypes were present 

 and none were added or lost. The same is true of the test of the Chalcicomula 

 colony ; none was added or lost in the test location. The test in this instance 



