192 McCLUNG. [Vol. II. 



elements of the testicular cells of Caloptemis femur rubrum, 

 Wilcox ^ notes that, while ordinarily the chromatin and the 

 nucleolus stain red and the cytoplasm green, by double staining 

 in safranin and victoria green, yet " in sonie'^ stages the chromo- 

 somes were stained green, indicating that a chemical change 

 takes place in the chromatic substance. But even in such cases 

 the nucleolus was bright red." 



Again, he states that " by this method (Henneguy's) the 

 chromosomes and nucleoli are stained bright red." With refer- 

 ence to the changes occurring in Cicada, this alternation of 

 staining power is noted particularly in the following language : 

 " By the safranin and victoria green method the chromosomes 

 stain red, though not so deeply as the nucleoli. At later stages 

 the chromosomes assume a green color while the nucleoli con- 

 tinue to stain red. In still later stages the chromosomes again 

 take the red." 



All these color reactions ascribed to the nucleolus by Wilcox 

 are strictly parallel to those exhibited by the accessory chromo- 

 some in Xiphidiiim preparations, and there can be liiitle doubt 

 that the two elements are identical. Added force is lent to 

 this view by the appearance of the cells shown in Fig. 108 by 

 Wilcox, in which the nucleolus is represented just as the acces- 

 sory chromosome appears in the sperm-forming cells of XipJiid- 

 iiini. Moreover, with regard to the spermatogonial divisions, 

 he says : " In most cases a nucleolus is to be seen during the 

 prophases. In Fig. 106 there is in the nucleus a body (nucle- 

 olus {.■*) ) which seems to have recently divided." 



Later Wilcox refers to this same body, apparently, as a cen- 

 trosome which becomes included in the nuclear membrane and 

 goes to form the " neck " of the spermatozoon. He says : 



" Some of the spermatids stained by Henneguy's method, 

 and nearly all of those stained by Heidenhain's method, show 

 a spherical body near the chromatic mass {PI. V, Figs. 232-235), 

 and this body becomes included in the nuclear vesicle when a 

 membrane is formed (PL IV, Figs. 148 and 149; PI. V, Figs. 



1 Wilcox ('95), " Spermatogenesis of Caloptemis femur rubrum and Cicada 

 tibicen," Contribntiofts frotn the Zodl. Lab. of the Mus. of Com p. Zool. at Harvard 

 College, vol. xxvii, No. i. 2 italics in the original. 



