82 THEORY OF EVOLUTION 



that differ from each other markedly in color 

 patterns (fig. 43). When any two individuals 

 of these races are crossed they give, as Nabours 

 has shown, in F 2 a Mendelian ratio of 1: 2: 1. 

 It is obvious, therefore, that there are here at 

 least nine characters, any two of which be- 

 have as a Mendelian pair. These races have 



FIG. 43. Four wild types of Paratettix in upper line with 

 three hybrids below, (After Naboure.) 



