253 The Mechanism of Evolution in Leptinotaesa 



females, distributed in the four classes common to this biotype, and one group of 

 6 males and 1 female having some of the characters of primary biotype 3 (see fig. 

 40e). These divergent individuals were mated, the single male and a female 

 and gave a progeny in F5 of 21 males and 26 females, which were, however, all of 

 the primary biotype 2 character. From the normal group in F^, 2 of each sex 

 were taken at random from each of the classes, mated as the parents of F5, and 

 gave a progeny of 260 males and 274 females, with the usual distribution.' In 

 Fb each of the two groups were bred from and both gave in F, from the normal 

 131 males and 92 females. In the group B, 36 males and 35 females, all ia 

 both sets typical of the strain. The liaes A and B were continued, giving in F 

 in (A) 233 males, 191 females, (B) 65 males and 60 females, all true to type^ 

 and in Fg (A) gave 248 males and 279 females, (B) 131 males and 123 females] 

 likewise true to type. At the end of Fg the culture was killed off. 



GENERATION 



f . ' 1 



\Prv^eny: b c ^^ 



VI 1 ZOi/Sf tyisif Titos 



, I " ' 



Progeny: b c 



Mitted.: 3i 3f 2i 3f 



1 ■' 



\ Progeny :'~^ b c 5~^ 



/3< 4llf SS'f !06f BTlaZf loJ Bf 



\Mdted,: .Z'lf 3^3/ 3^3) 3S3f 



^ 1 ' 



Proffeny: a b c d i^ 



;? 90^96f I90il87f 77^61 f 6i J f 



Mated.: if zisf zS zf it Zf zijf 



\ ^^ . 



Progeny, abed ' ~b c 'd~~' 



77t87f l-IZJlSSl ff>3af lOilZl 3^112 2^31 



Mated.: ^ zizf zSzf ztzf ^4^^ ^j^^ ^^^^ 



f ) \ 



\ Progeny: a bed a b c d~' 



'■«1 *'' 3l'-fZf 86i3Sf Willf . Ii3f 9il4f zzimf 4^ 



yMated,: zt zi Zf zi Zf zizf liZf Z^Zf zip.f zt 



( 1 ir 



\ Progeny: abed ^ 1 g 



^tK l'3f 14ilSf l')etl3St 4Zt3lf zijf isizif 4^63 



{Mated: i^zf zi Zf zt zs z^zf zin zizs zt < 



38 f zt 



{Progeny: abed ^s b c ^ 



'■«! It 9Sti03f U6t}7lf zt zi4f 3lt4.7f S6t74f 



Fio. 40. — Showing breeding record of a primary Wotype 2 of L. multitceniata 

 tlirough a series of generations and the constancy of the pattern produced in these 

 biotypic lines. 



In this test with primary biotype 2, when reared as a group culture with 

 matings at random and perfectly free interbreeding of the parent groups, the 

 culture remained stable throughout. Only in generation 4 did the population 

 overstep the normal range, and these, separated and reared iadependently, 

 proved not to be a gametic change, but only a somatic (?) disturbance, as shown 

 by the giving of typical biotype 2 pattern all through the line (B), with no 

 reappearance of the divergent examples of generation 4. In a cultuie of this 

 character there is no intentional selection and no evidence of selection of any 

 sort. The conditions of life were kept as uniform as possible and care was 



