M'CLUXG : SPERMATOCYTE DIVISIONS OF THE LOCUSTID.K. 187 



stain, but it is frequently advantageous to trace the chemical 

 changes undergone by the different cell elements in the process 

 of mitosis, and the aniline stain above mentioned serves excel- 

 lently for this. Kernschwarz has also been found a valuable 

 stain for some purposes. 



III. NOMENCLATURE. 



The terminology as outlined in a former paper (17) will be 

 followed in the present one. 



IV. OBSERVATIONS. 



(«) General Form and Structure of the Testes. 



The testes of the Locustidte are paired structures lying in the 

 anterior dorsal portion of the abdomen. Each organ is made up 

 of numerous short follicles, which are bound together by a con- 

 nective tissue investment. In adult animals the testes are a, 

 bright yellow color, while in nymphs the color varies from 

 white in the youngest to yellow in the oldest. The pigment 

 is lodged in the connective tissue sheath about the testis, and is 

 seen in sections as irregularly rounded masses in the cytoplasm. 



(b) The Spermatogonia. 



No further discussion of the spermatogonia will be given 

 here than is necessary for an understanding of the derivation 

 of the first spermatocytes. As appears to be universally the 

 case, the second spermatogonia, in their last generation at 

 least, are much reduced in size as compared with the primary 

 spermatogonia that preceded them and with the first sperma- 

 tocytes that arise from them. The entire cell stains dark with 

 almost all stains and, as the nucleus occupies nearly the whole 

 cell body, the chromatin appears relatively large in amount. 

 A cyst of spermatogonia, therefore, looks as if composed almost 

 entirely of chromatin aggregated into rounded masses — the 

 nuclei. 



The chromosomes are of the rod type, and divide longitudi- 

 nally in each mitosis. The number of chromosomes is large 

 and could not be determined with absolute certainty, but a 

 number of careful enumerations makes it evident that there are 

 most probably thirty-three. In most species of Locustids, one 

 chromosome is easily distinguished from the others by its larger 

 size and tardy division in the act of metakinesis. This is the 



