Kansas University Science Bulletin. 



Vol. IV, No. 14. SEPTEMBER, 1908. l^o"°x%?5aH' 



ORGANIZATION OF THE CHROMOSOMES IN 

 PHRYNOTETTIX MAGNUS. 



BY EDITH PINNEY. 



(Contribution from ttie Zoological Laboratory, No. 181.) 

 Plates XXIII, XXIV. 



CYTOLOGICAL investigations in this laboratory on the 

 spermatogenesis of various Acrididx have resulted in 

 discoveries of primary importance concerning the pre- 

 cision in the organization of the Acrididsean chromosomes. 

 McClung, in a comparative study of "The Chromosome Com- 

 plex of Orthopteran Spermatocytes,"* finds that a "definite 

 series of chromosomes" occurs in all the members of the fam- 

 ily, and that the modifications in size, form and association of 

 these elements accompany variations in somatic characters 

 that account for the division of families into genera and 

 species. Striking examples of the constancy of such modifica- 

 tions were found in the multiple chromosomes of Hesperotet- 

 tix and Mermiria, which he describes. In establishing the in- 

 dividuality of the chromosomes different workers have found 

 these elements exhibiting constant characteristics of size, 

 form and function. 



In my brief study of the male germ-cells of Phrynotettix 

 magnus I have found further convincing evidence of a precise 

 and definite order governing the cell processes exhibited in the 

 internal organization of the chromosomes. The work was 

 done under the direction of Doctor McClung. The investiga- 

 tions of McClung on the "Spermatocyte Divisions of the Acri- 

 didse"f and Sutton on the "Spermatogonial Divisions of Brachij- 



* Biological Bulletin, vol. 9, No. 5, 1905. 



t Kansas University Quarterly, vol. 9, No. 1, 1900. i 



(309) 



