THE ORIGIN OF GYNANDROMORPHS. 45 



No. 5238. September 23, 1916. C. B. Bridges. Text-figure 28 (diiigram). 



Parentage. — One of the X chromosomes of the mother carried the genes 

 for vermihon eye-color and for bar eye, the other X the gene for forked 

 bristles. The X chromosome of the father carried the genes for eosiii, 

 vermilion, and forked. 



Description. — The fly was mainly female, but is exceptionally interesting 

 from the peculiar description of the male parts, which constitute a v(;ry 

 narrow stripe running through the middle of the left eye and along the left 

 side of the thorax, including the wing. The left eye was eosin vermilion in 

 color in the male parts and red in the female parts, both above and below the 

 eosin vermilion. These female parts were heterozygous for bar and the red 

 portions above and below were therefore characteristically narrow, while the 

 eosin-vermilion part was not-bar and projected forward, so that the male 

 stripe could be traced forward to the normal margin of the round eye. The 

 male part of the thorax could likewise be traced by means of the forked 

 bristles, of which there were three anterior to the wing, one above, and none 

 below. The wing itself was included in the male region and was smaller 

 and had forked marginal bristles. There was no sex-comb on the left side. 



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

 was fertilized by the eosin vermilion forked sperm. A maternal X suffered 

 elimination, leaving the eosin vermilion forked X to produce the male parts. 



B 



W^ V f W V f 



No. 2. September, 1917. T. H. Morgan. Text-figure 29 (drawing). 



Parentage. — The fly appeared in "selected notch" stock in which, in each 

 generation, red-eyed notch females were bred to eosin ruby 

 males. 



Description. — The right eye was red, the left partly red, 

 partly eosin ruby, with a very irregular boundary-line; other- 

 wise the fly was female. 



Explanation. — An egg with a gene for notch wing was fer- 

 tilized by an X sperm bearing eosin and ruby. Elimination 

 of one of the maternal X's left a part of one side of the head 

 with the eosin ruby X. The wings, although not showing 

 notch, must have contained the gene. Since less than half text-fioure 29. 

 of the notch flies in this selected stock showed the notch 

 character, its absence here is not diflficult to explain. 



W Vb W' rb 



No. 477. October 31, 1917. D. E. Lancefield. Text-figure 30 (drawing). 



Parentage. — One of the X chromosomes of the mother had a bar gene, 

 the other a gene for forked. The father was bar. 



Description. — The head was small, with round eyes and forked bristles. 

 The thorax and wings seemed to be female. No sex-combs present. The 

 abdomen was entirely female, with eggs inside, but she did not breed. 



