320 



The Mechanism of Evolution in Leptinotaesa 



5 15 8 



29— (3 



31 ---^\\' 



42 ^ \Vi!¥j^ 



47 (^ \(£m2) 



86- 

 74-. 

 83- 



dstf^ — 17 



^- 22 



^) 51 



^ 74 



■^) (^ ^ 45 



14 2 12 9 



I / / /' 



©tfg) 



(^- 



91 



183 



171 



^). 146 



m^ 211 



^^ 145 



(^ ,7 



1653 Males. Total 2774. 



17 



20--® 



51—^ 



42 (^ 



26 



21 



W// $^-14 



^' ^—-49 





74 



81 



— -192 

 ---186 



144 



93 



74 



1121 Females. 



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

 11 7 



41_i^ \\ 

 77_-(^ \^> 

 92 ^> ^ 



^ 20 



^ 58 



(^g) 55 



^ 92 



^Jg) 46 



55 ^ ^r -183 



19 ^ ^■ 



^- 



179 



-155 



177 



92 



-36 



41 



8 5 4 1 



25-^ m// ^__, 



33—-^ <^/ ^^_.._31 



•36- — -® ^ ^ 44 



31 -W> ^ 88 



17 -^ ^ 166 



^ 75 



^. 56 



^i 42 



& '' 



1454 Males. Total 2152. 698 Females. 



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

 pattern. 



8 17 



9 5 



5- 



7-— ( 



\ 31 4 



(^n^u-^ii 



^ 46 



^ 92 



^ 88 



^ 107 



-W> ^ 100 



■-~^> '^ 58 



^ 177 



1^ 96 



1^, 109 



^, 77 



;r--, 41 



18 ^ ^ 



41 



12 



i— @> 



/ / 



4 



71 M> 



66 M 



69 — 



<«2B>— 31 



^ 20 



^ 21 



^^ 74 



^ 55 



_^ ^L 83 



^^ 155 



^_ 86 



l^k 77 



^ '42 



^ 51 



^jny 12 



1145 Males. Total 20S4. 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 hoth sexes. 



