THE ORIGIN OF GYNANDROMORPHS. 



53 



GYNANDROMORPHS PRODUCED BY XXY FEMALES. 



No. N 2. December 12, 1912. C. B. Bridges. Plate 3, Figures 1 and la 



(colored drawings). 



Parentage. The mother was an XXY female homozygous for white and 

 heterozygous for the third-chromosome mutant pink. The father was red- 

 eyed, and also heterozygous for pink. Both parents were exceptions produced 

 by secondary non-disjunction. 



Description. The fly was a completely bilateral gynandromorph, male 

 on left side, female on right. The male side was smaller, with sex-comb, 

 the genitalia half and half. The fly was unable to breed as a male or as a 



TEXT-FIGURE 41. 



TEXT-FIGURE 42. 



TEXT-FIGURE 43. 



TEXT-FIGURE 44. 



female. The abdomen was large and evidently contained a pair of ovaries. 

 The fly was figured in Heredity and Sex, page 163, and the origin given in 

 Journ. Exp. Zool., 1913, page 597. 



Explanations. A regular X egg carrying the gene for white was fertilized 

 by an X sperm carrying the wild-type allelomorph red. One of the maternal 

 X's, bearing the gene for white eye, was eliminated. The white-eye character 

 therefore does not appear on either side. As both parents were heterozygous 

 for pink, the fly may have come from third chromosomes bearing normal 

 genes only, or one of them may have had the gene for pink, so that! the gynan- 

 dromorph is heterozygous. 



w 



No. N 3. November 30, 1912. C. B. Bridges. Plate 3, Figures 2 and 2a 

 (colored drawings). (See fig. 17.) 



Parentage. The mother was an XXY female, carrying white in both X 

 chromosomes. The father was a wild male. 



