292 



T. H. MORGAN 



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PHYLLOXERA CARYMCAULIS 





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 9 



Diagram 1 Illustrates the chromosomal cycle of Phylloxera carj^aecaulis; 

 to the left is shown the line that culminates in the sexual female ; to the right is 

 shown the line that culminates in the males; this line splits into two subdivisions 

 after the extrusion of the polar body in the male-producing egg. 



