228 



The Mechanism of Evolution in Leptinotarsa 



some of the lines from the mere fact of growing them under uniform and con- 

 stant conditions ; but no such effect was found. 



All of the strains hibernated from late December 1907 to the first of March 

 1908, and were then mated within the same lines at random and in the same 

 set of conditions, giving a generation in April and a second one in late May and 



Table 30, 



No. of mating. 



1. gn(A) ., 



l.g 11(B) ., 



l.g 11(C) . 



8. gn(A) ., 



8. g 11(B) ., 



10. g 11(A) . 



10. g 11(B) . , 



10. g n(C) . , 



10. g n(D) . 



1. g m(AA) 

 1. g in(BA) 

 1. g in(CA) 



8. g III(AA) 

 8. g m(BA) 

 IC. g ni(AA) 

 10. g III(BA) 



10. g m(CA) 



10. g III(DA) 



Progeny. 



Fraternity No. 



1. g ra(A) 

 1. g ni(B) 

 1. g ni(C) 

 8. g ni(A) 

 8. g in(B) 

 10. g m(A) 

 10. g m(B) 

 10. g m(C) 

 10. g in(D) 



Range of index. 



Totals. 



341 

 35) 

 23) 

 29) 

 331 

 40) 

 26) 

 23) 

 20) 

 19) 

 14) 

 16) 

 16) 

 17) 

 28) 

 23) 

 16) 

 24 f 



Total 436 



1. g IV(AA) 

 1. g IV (BA) 

 1. g IV(CA) 



8. g rv(AA) 



8. g IV(BA) 

 10. g IV(AA) 

 10. g IV(BA) 

 10. g IV (CA) 

 10. g IV(DA) 



40 



52 



48 



I 25 



i- 



!'■ 



I 35 



I 23 



I 30 



Total 336 



early June of 1908. Identical methods were followed in both of the 1908 gen- 

 erations, with no change in the result, as far as the range in the index was 

 concerned. 



It was most surprising to find that in the different lines all carried under 

 controlled conditions, with random matings, that the range in the index was not 



