198 



ROBERT H. BOWEN. 



rise to the expected haploid and diploid chromosome complexes 

 in the maturation divisions. The fact that in synapsis (and 

 subsequent stages) the homologous pairs of chromosomes behave 

 exactly as though they were present in the diploid number, is an- 

 other fact of great theoretical significance. This last-mentioned 

 point is of particular interest because of the condition recently 

 reported in a triploid specimen of Canna by Belling ('21). This 

 author finds that in the pollen-mother-cells there are nine triads 

 (the haploid number is nine), "each of which separates into 

 two and one on the spindle, in a random manner with regard to 

 the two poles." In the tetraploid individual of Euschistus, on 

 the other hand, no indication of a tendency to form multiple 

 groupings of this kind has been observed at any stage. . 



LITERATURE CITED. 

 Belling, J. 



'21 The Behavior of Homologous Chromosomes in a Triploid Canna. Proc. 



Nat. Acad. Sci., Vol. 7. 

 Bowen, R. H. 



'20 Studies on Insect Spermatogenesis. I. The History of the Cytoplasmic 



Components of the Sperm in Hemiptera. BIOL. BULL., Vol. 39. 

 '22 S'tudies. IV. The Phenomenon of Polymegaly in the Sperm Cells of 



the Family Pentatomidcc. Proc. Am. Acad. Arts and Sciences, Vol. 



57- 

 Bridges, C. B. 



'21 Triploid Intersexes in Drosophila melanogaster. Science. N.S., Vol. 54. 

 Gates, R. R. 



'09 The Stature and Chromosomes of CEnothera gigas, De Vries. Arch. 



f. Zellforsch., Vol. 3. 

 Hartman, F. H. 



'13 Giant Germ Cells in the Grasshopper. BIOL. BULL.. Vol. 24. 

 Henking, H. 



'91 Untersuchungen ueber die ersten Entwicklungsvorgaenge in den Eiern 

 der Insekten : II. Ueber Spermatogenese und deren Beziehung zur 

 Eientwicklung bei Pyrrhocoris. Zeitsch. f. wiss. Zool., Vol. 51. 

 Montgomery, T. H. 



'n The Spermatogenesis of an Hemipteron Euschistus. Jour. Morph.. 



Vol. 22. 

 Morgan, T. H. 



'15 The Predetermination of Sex in Phylloxerans and Aphids. Jour. Exp. 



Zool., Vol. 19. 

 Paulmier, F. C. 



'99 The Spermatogenesis of Anasa tristis. Jour. Morph., Vol. 15 Supple- 

 ment. 



