SEX INHERITANCE 



101 



One of them, XxXx, produces eggs which, after 

 extruding one polar body, give rise to the migrants 

 bearing large eggs; from the latter eggs, in turn, come 



XxX: 



3TtM nOTHER-FtmLCTROOUCING UNE 



XxXx' 



arm none* - MALC-ntoouoNC UNE 



XxX: 



MIGRANT -FEMALE PRODUCER 



XxX 



2"" GENERATION 



XxXx 



FEMALE 



Xx 



HALE-TYPE I 



Xx' 



MALE. TYPE H 



POLAR SPINDLE 



FEttAI-E PRODUCING 

 5PCRM 



FIG. 35. Diagram to illustrate the chromosomal cycle of Phylloxera 



caryaecaulis. 



