40 Hewitt, Cytological Aspect of Parthenogenesis in Insects. 



Plate II. 



I. Formation of polar nuclei in parthenogenetic egg of Apis 

 (after Petrunkewitsch). 



Fig. 8. Second polar mitosis, each of the three polar nuclei 

 and the egg nucleus contain 8 chromosomes, the 

 reduced number. 



Fig. 9. Fusion of the inner half of the first polar nucleus and 

 the second polar nucleus to form the syntelosome 

 ( Petrunkevvitsch's " conjugation-nucleus "). 



Fig. 10. The degeneration of the first polar nucleus, and 

 wandering inwards of the egg nucleus. The syntelo- 

 some contains 16 chromosomes. 



2. Formation of polar nuclei in parthenogenetic egg of Poecilosoma 

 luteolum (diagrammatic after Doncaster). 



Ftg. II. First polar spindle. 



Fig. 12. Second polar mitosis. 



Fig. 13. Egg nucleus and three polar nuclei : inner largest, 



outer smallest. 

 Fig. 14. Degeneration of polar nuclei and inward migration 



of egg nucleus {e). 



