THE ORIGIN OF GYNANDROMORPHS. 41 



No. 29. February 11, 1918. T. H. Morgan. Text-figure 21 (drawing). 



Parentage. Both mother and father were eosin. 



Description. The gynandromorph was bilateral, except that the entire 

 head was female, having eosin eyes of the dark homozygous eosin color. 

 The left side was male, having a sex-comb, shorter legs, shorter bristles and 

 wing, and a smaller left side to the thorax and abdomen. The coloration 

 of the abdomen was half and half, but there appeared to be a pair of ovaries 

 and female genitalia. 



Explanation. An egg containing an X chromosome with the gene for 

 eosin was fertilized by an X sperm carrying eosin. Elimination of either 

 X gave the nearly bilateral gynandromorph. 



w e w e 



GYNANDROMORPHS MAINLY FEMALE. 



No. C 2 C 19 . January 1914. E. M. Wallace. Plate 2, Figure 3 

 (colored drawing). 



Parentage. The mother was white-eosin compound, having the genes for 

 yellow and white in one X and eosin in the other X. The father was eosin. 



Description. All of the fly was gray and female, except the upper right 

 half of the thorax and the right wing, which were yellow and male. Both 

 eyes were eosin, of the dark type of the homozygous eosin female. Well- 

 developed ovaries were present on both sides. Mated to a yellow white 

 male this gynandromorph was fertile and produced white-eosin females 70; 

 eosin males 42; yellow white-eosin females 53; yellow eosin males 58. 



Explanation. An egg with a cross-over X containing the genes for yellow 

 and eosin was fertilized by an X sperm with a gene for eosin. Elimination 

 of one of the latter left the maternal X to produce the male parts on the 

 upper right side of the thorax. 



yw e yw e 



vcl* 



No. 5137. September 4, 1916. C. B. Bridges. Plate 2, Figures 5 and 5a 



(colored drawings). 



Parentage. The mother had one chromosome with the genes for vermilion, 

 sable, garnet, and forked, and the other X with the genes for vermilion and 

 for bar. The X-bearing sperm carried the genes for eosin and for miniature 

 wings. 



Description. The mosaic was entirely female, except for a patch of eosin 

 in the left eye. The eosin part of the eye was round and light eosin (male 

 type) while red bar both above and below (very slight amount below). The 

 right eye was red bar. The whole abdomen was full of eggs. 



Explanation. An egg with the X chromosome carrying the genes for 

 vermilion and bar was fertilized by a sperm carrying the genes for eosin and 

 miniature. Elimination of a maternal chromosome took place, leaving the 



