Kansas University Science Bulletin. 



Vol. I, No. 8. 



SEPTEMBER, 1902. 



Whole Sebies, 

 Vol. xi. No. B. 



THE SPERMATOCYTE DIVISIONS OF THE LOCUSTIDJE. 



BY C. E. M'CLUNG. 

 With Plates VII, VIII, IX, and X. 



I. Introduction. 

 II. Methods. 



III. Nomenclature. 



IV. Observations. 



(a) General Structure and Form of the 



Testes. 



(b) The Spermatogonia. 



(c) The First Spermatocytes. 



(d) The Second Spermatocytes. 



(e) The Spermatids. 



V. Comparisons and Conclusions. 



(a) Nomenclature. 



(b) The Spermatocytes of the Acridida? 



and the Locustidse. 



(c) Formation of the Tetrads. 



(d) The Spermatocyte Divisions. 



(e) The Accessory Chromosome. 



(f ) Individuality of the Chromosomes. 



(g) Nucleoli, 

 (h) Rest Stage. 



VI. Summary. 

 VII. Bibliography. 



I. INTRODUCTION. 



Under the title, "A Peculiar Nuclear Elemeut in the Male 

 Reproductive Cells of Insects" (16) , I published a preliminary 

 account of the process characterizing the maturation divisions 

 of the Locustidse. This was of a general character and served 

 merely as a basis for a description of the accessory chromosome 

 in these cells. It is my present intention to give a detailed his- 

 tory of the spermatocyte divisions occurring in this family, 

 after the manner followed previously in considering correspond- 

 ing stages in the Acrididse (17). Besides giving this account 

 of processes, however. I shall be able to draw T some compari- 

 sons between the two families. Eventually I hope to complete 

 such a comparative study of all the Orthopteran families. Ma- 

 terial for this larger investigation is now partially on hand, 

 and is being added to as circumstances permit, so that it may 

 be possible to carry through a study of the maturation stages 

 in this order of insects within a few years. 



(185) 



