THE GERM-CELLS OF CICADA (TIBICEN) SEPTEMDECIM. 425 



These represent "sans doute le produit de secretion des cellules 

 interstitielles." Athias is of the opinion that the mitochondria 

 are transformed into lipoid globules by a change in their chemical 

 constitution. " On observe tres souvent des images qui montrent 

 que le produit graisseux doit resulter d'un changement chimique 

 de la substance mitochondriale; on peut suivre, en effet, les 

 differentes phases de la transformation des plastosomes en gout- 

 telettes de graisse" (page 195). 



What the significance of such cellular degeneration, as found 

 in the testes of Cicada, can be is difficult to say, since it occurrs 

 regularly and is moreover found in almost all insect testes. It 

 may possibly be that these degenerated cells in some way supply 

 nutriment to the spermatozoa, as suggested by Wieman ('10) 

 in the case of degenerated cells in the testes of Leptinotarsa, and 

 are hence homologous to the nurse cells of the ovaries. I have 

 often noticed deeply staining bodies, somewhat resembling the 

 degenerated cells, lying among the spermatozoa; but other than 

 this there is no evidence that the degenerated cells are a source 

 of nutriment for the spermatozoa. 



(b) Spermatocytes. Since the spermatocytes of the early 

 growth period are not present in my material, it has been im- 

 possible to follow the mitochondria from the last spermatogonial 

 division into the spermatocytes. However, in the pachytene 

 stages (Fig. 17) mitochondria are present in the form of filaments 

 which sometimes appear granular. As will be noticed they are 

 most abundant at the pole of the cell where the idiozome is 

 located, which is the usual localization of the mitochondria in 

 the spermatocytes, but which is by no means general. In 

 Passalus (Shaffer, '17) I have found that the mitochondria of 

 the early spermatocytes are in the form of diffusely spread 

 granules and are often most abundant in a zone immediately 

 surrounding the nucleus. 1 Undoubtedly, the filar mitochondria 



1 Duesberg ('18) has questioned these observations stating (foot-note, p. 138): 

 "it is characteristic, even if not quite general, that the male auxocytes have their 

 chondriosomes accumulated at one pole of the nucleus around the idiozome." 

 Duesberg's ('10) own figures (Figs. 51, 52, 53) of the spermatocytes of the guinea- 

 pig seem to contradict this, for he describes the mitochondria as being spread 

 diffusely in the cytoplasm. "Us (mitochondria) cessent d'etre groupes exclusive- 

 ment autour de 1'idiozome, pour se repandre dans toute le cytoplasme" (p. 65). 



