n; 



HEREDITY AND SEX 



united \H). Two divisions lake place (C, D), when the 

 two polar bodies are formed, leaving seven chromosomes 

 in the egg E). Each egg contains as a result only one 

 .V chromosome. 



Any egg of lygseus fertilized by a sperm carrying an 

 A' chromosome produces a female that contains two 



Fig. 25. 



- or XX. Any egg fertilized by a sperm containing 

 chromosome produces a male that contains one 



a 



X and one )', or A')'. 



Another insect, Oncopeltus fasciatus, represents a 

 thud type m which the chromosome groups in the 

 male and in the female are numerically alike and alike 

 as to visible size relations. 



