320 



The Mechanism of Evolution in Leptinotaksa 





5 15 8 

 29 -- ^'\ \ \ 



42 ^\\^ ^^ 51 



47 (^ \^^ 1^ 74 



86 (^ («^ ^^ 



45 



74 i^w;^ li^ 91 



83 (^ 1^ 183 



(^>- 171 



^). 146 



W- 211 



^- — 145 



^SB> 77 



1653 Males. Total 2774. 



17 

 20--^ 



51 & 



42 (^ 



26 ^ 



21 



14 2 12 9 



.' / 



m 

 ^ 



(^—14 

 7 ^ 49 



^ m- 74 



81 



192 



186 



^L 144 



^^ 93 



^ 74 



1121 Females. 



FiQ. 141. — First annual generation at Chicago in 1904. 



W <^— 20 



.58 



\ \ 



41- i^ 



77— (^ \^ 



92 (^ ^ 



56 



19 



-m 



^ 55 



^ 92 



^^ 46 



(^ -183 



$'- 1'^ 



m^ 155 



^ 177 



-92 



-36 

 -41 

 • 17 

 Total 2152. 



27 



25--^ 

 33—-^ 



31-—^ 

 17 



8 5 4 1 



\ I ' f 



1 1 : 



mi 



m — 



<^— -- 



1454 Males. 



^ 9 



^ 31 



^ 44 



^ 88 



ii 166 



75 



^. 56 



42 



698 Females. 



Fia. 142. — Second annual generation at Chicago in 1904, showing the pronotal 

 pattern. 



8 17 

 X \31 4 



5-^\\\\ 



^ 46 



--^ 



^ ^ 



92 



& ^; 



-107 



18 ^ 



41 @ (^ 100 



12- -^ "^ 58 



(^ 177 



^ 96 



^:. 109 



^, 77 



4 



71 J^ 



66 & 



69 



41 



9 5 



// 



/ ^— 31 



' (^ 20 



^ 21 



74 



55 



_^ ^. 83 



155 



^. 86 



®- 77 



^ 42 



(^ 51 



^. 12 



1145 Males. Total 2084. 939 Females. 



Fig. 143. — First annual generation at Chicago in 1905, showing conditions In 

 population and existence of biotype 4 as an isolated group in both sexes. 



