6 



Iff 



t t • 



J{lt#«< 



f>n Mm 



t( f • • • 4 



Fig. 112. 

 Chromosome group of male and of female Protenor, the former 

 having one X-chromosome and no Y -chromosome; the latter having 

 two X-chromosomes. (After Wilson.) 



••• 



«r 



Am 



•••itt# 

 tin •*• 



Fig. 113. 



The male and female type of chromosome groups of Lygaeus, the 

 former with X and Y; the latter with two X-chromosomes. (After 

 Wilson.) 



