THE MUTATED GENE 



55 



curve, though starting with eggs of the same size, becomes 

 different from the onset of development. 



Exactly the same was found by Goldschmidt (1933a) for the 

 differences in size of geographic races of Lymantria disjpar. 

 Figure 18 represents curves of growth for three such races, female 



2000 



1800 



1600 



1400 



1200 



1000 



800 



600 



400 



200 



° Hich'moe 



1 Central 



/J Mas sac h 



• o* ' Hachiman 



/ SH<? 's* J Central 

 4H<?^s , * </ tiichinoe 



E 



m 



nr 



Pu 



Fig. 18. — Growth curves plotting larval instars against weight in milligrams 

 for caterpillars of Lymantria dispar of different size-races. (From Goldschmidt, 

 1933, Arch. Entwicklgmech. 130, Fig. 16.) 



and male, with weight plotted against the larval instars. The 

 differential growth rates become visible as soon as they are 

 measurable. 



As an example from plants, the observations of Muntzing 

 (1932) on Galeopsis tetrahit may be mentioned. Here flower 

 color and speed of development are correlated, the white-flowered 

 plants beginning to flower later than the red ones. It was shown 



