6 



Iff 



f t • 



]!••••• 



0rf If • » 

 €(f I • t « 



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-ehromosomes. (After Wilson.) 



••• 





? 





•Ctliti 



fill •#• 



Fig. 113. 



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

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

 Wilson.) 



