PARTHENOGENESIS 175 



the same egg will produce, if it is fertilized, a female 

 (queen or worker), or, if it is not fertilized, a male 

 (drone). If the queen deposits an egg in a cell of the 

 comb that has been built for a queen or a worker, she 

 fertihzes the egg ; if in a drone cell, the egg is not fertil- 

 ized. We need not conclude that the queen knows 

 what she is about — the difference in shape of the drone 

 cell may suppress the reflex, that in the other cases 

 sets free the sperm. 



The case of the bee has attracted so much attention 

 that I may be allowed to pause for a moment to point 

 out some of the most recent results connected with the 

 formation of the germ-cells. 



The egg produces two polar bodies — the process 

 being completed after the sperm has entered the fer- 

 tilized egg (Fig. 90). Eight chromosomes are present 

 at each division. Eight remain in the egg (these are 

 double chromosomes — therefore 16). The sperm 

 brings in 8 (double) chromosomes so that the female 

 comes to have 16 single chromosomes in her cells. There 

 is only one kind of spermatozoon, as shown by the figure, 

 for the first spermatocyte division is abortive — all 

 the chromosomes passing into one cell only, and the 

 second division gives rise to a small cell, that does not 

 produce a spermatozoon, and a large cell that becomes 

 a spermatozoon. 



If the egg is not fertilized, it also gives off two polar 

 bodies. It has 8 chromosomes left. The male de- 

 velops with the half number. The formula for the 

 female will be XABCD XABCD and for the male 

 XABCD. 



If the bee conforms to the ordinary type for insects. 



