THE GERM-CELLS OF CICADA (TIBICEN) SEPTEMDECIM. 43! 



adult ovaries, the egg-strings loose their cytoplasmic appearance 

 and seem to be of a fibrous structure (Figs. 34, 45, 47, e.s.). 

 This fibrous appearance of the egg-strings has often been figured 

 in the ovaries of other insects, but I am inclined to doubt its 

 normality; it seems rather that the fibrous appearance is due 

 to fixation and really represents a compression of the cytoplasmic 

 processes of the oocytes. 



In the nurse chamber, the nurse-cells are arranged in what 

 appears to be a syncytium, and only occasionally can cell-walls 

 be distinguished. In the young pupse, the egg-strings of the 

 oocytes pass through the region of the follicle-cells into the nurse 

 chamber and seem to fuse and become continuous with the cyto- 

 plasm of the nurse-cells. In the adult ovaries when all the cells 

 are at the height of their functional activity, the egg-strings 

 become much enlarged assuming the fibrous appearance above 

 described. In the nurse chamber, the egg-strings end in a 

 central fibrous mass (Figs. 34, 71, 72, i.n.c.), the substance of 

 which is continuous with the egg-strings and from which they 

 lead to the oocytes. The nurse-cells immediately in the region 

 of the central plasmatic mass stain deeply and show evidences of 

 degeneration. Within the plasmatic mass can be seen many 

 nurse-cell nuclei in various stages of disintegration (Figs. 72, 34, 

 i.n.c.). The nuclei become smaller, staining intensely, and finally 

 become broken down and the products of their disintegration 

 can be seen passing down the egg-string into the oocyte (Figs. 

 45, 71). The nurse-cells are thus ingested by the protoplasmic 

 process of the oocytes which are probably furnished with some 

 substances (enzymes) enabling them to digest the nurse-cells. 

 In the adult ovaries, at the height of the breeding season, the 

 ingestion of the nurse-cells has taken place to such an extent 

 that almost half of the nurse-cells have disappeared and the 

 central plasmatic mass has grown in size containing a great 

 many ingested nurse-cells. The growth of the central plasmatic 

 mass is undoubtedly correlated with the disappearance of the 

 nurse-cells in this region of the ovary. 



It is a noteworthy fact that the ingestion of the nurse-cells 

 takes place at a time when there is a rapid growth of the oocytes. 

 The oocytes at the beginning of the synaptic processes have large 



