JsTo. 642] VARIATION IN SEX CHARACTERS 55 



In an outcross of a haplo-IV individual to a normal, 

 the entire complex of characters is inherited as a simple 

 dominant and gives a 1 : 1 ratio, except that the haplo- 

 lA^'s are less viable. Likewise in outcrosses of haplo-X 

 individuals the entire complex of male characters is in- 



herited as a siiiii)le dominant and gives a 1 : 1 ratio except 

 that the haplo-X 's are somewhat less viable. 



When a haplo-IV individual is mated to a recessive 

 whose gene is in the fourth-chromosome, all the haplo- 

 fourth offspring show this recessive— a behavior that is 

 strictly parallel to sex-linked inheritance ; for if a haplo-X 

 individual, that is, a male, is mated to a recessive whose 

 gene is in the X, all the haplo-X offspring show this re- 

 cessive. 



The fourth-chromosome recessive chnraetors present in 

 haplo-IV individuals from tlu er()>s ol' a Implo-fourth to 

 the recessive show a grade o( develoitiiieiit that is differ- 

 ent from their grade as homozygous characters in diplo- 

 IV's. This phenomenon is known as ''exaggeration," 

 and is interpreted as the effect of an unbalance within the 



