CHAPTER VI 



Gynandromorphism, Hermaphroditism, 

 Parthenogenesis, and Sex 



Three different sex conditions occur in animals and 

 plants that have a direct bearing on problems of 

 Heredity and Sex. • 



The first condition is called Gynandromorphism — 

 a condition in which one part of the body is like the 

 male, and the other part like the female. 

 1 4 The second condition is called Hermaphroditism — 

 a condition in which the individuals of a species are all 

 alike — maleness and femaleness are combined in 

 the same body. Two sets of reproductive organs are 

 present. 



The third condition is called Parthenogenesis — 

 a condition in which the eggs of an animal or plant 

 develop without being fertilized. 



gynandromorphism 



Gynandromorphs occur most frequently, in fact 

 almost exclusively, in insects, where more than one 

 thousand such individuals have been recorded. They 

 are most abundant in butterflies, common in bees 

 (Fig. 81) and ants, rarer in other groups. They 

 occur relatively more often, when two varieties, or 

 species, are crossed, and this fact in itself is signifi- 

 cant. A few examples will bring the cases before us. 



In my cultures of fruit flies several gynandro- 



161 



