ORIGIN OF MYCETOCYTES IN PSEUDOCOCCUS. 295 



identical with problems that have troubled the cytologist for 

 years. 



SUMMARY. 



1. The first and second polar bodies of Pseudococcus undergo 

 fusion and form a polar nucleus. This contains 15 chromosomes. 



2. The polar nucleus divides several times (probably a definite 

 number of times) giving rise to the polar derivatives. 



3. The polar derivatives may fuse with either migrating 

 cleavage cells or with each other to form the giant cells. The 

 numerical data furnished by chromosome counts as well as the 

 purely cytological evidence support each other in arriving at this 

 conclusion. 



4. The giant cells migrate from the periphery to the symbionts 

 to enter into association with these. When this process has been 

 completed, the giant cells are known as mycetocytes. 



5. Discussion regarding the nomenclature of the cells involved 

 in these phenomena. Statement of the problems presented 

 during the various stages of the investigation. 



REFERENCES. 

 Bowen, R. H. 



'22 Notes on the Occurrence of Abnormal Mitoses in Spermatogenesis. BIOL. 



BULL., Vol 34. 

 Breest, Fr. 



'14 Zur Kenntniss der Symbionteniibertragung bei viviparen Cocciden und 



bei Psylliden. Arch. Protistenk., Bd. 34. 

 Buchner, Paul. 



'21 Tier und Pflanze in intrazellularer Symbiose. Gebriider Borntrager, 



Berlin. 

 Haecker, V. 



'95 Ueber die Selbstandigkeit der vaterlichen und mutterlichen Kernbestand- 

 teile wahrend der Embryonalentwicklung von Cyclops. Arch. mikr. 

 Anat., Bd. 45. 

 Morrill, C. V. 



'10 The Chromosomes in the Oogenesis, Fertilization and Cleavage of Coreid 



Hemiptera. BIOL. BULL., Vol. 19. 

 Pierantoni, U. 



'10 Ulteriori osservazioni sulla simbiosi ereditaria degli Omotteri. Zool. Anz., 



Bd. 36. 



'n Sul corpo ovale del Dactylopius citri. Boll. Soc. Natur. Napoli. Vol. 24, 

 '13 Struttura ed evoluzione dell'organo simbiotico di Pseudococcus citri Risso, 

 e ciclo biologico del Coccidomyces dactylopii Buchner. Arch. Protistenk. 

 Bd. 30. 



