CHROMOSOMES OF TIGER BEETLES 445 
4, THE SPERMATOGONIA 
Of the five species presented in this study, only a few minor 
differences in the cellular behavior were found. ‘The differences 
were not sufficiently great to warrant a separate discussion for 
each species. Unless otherwise specified, the descriptions and 
drawing are based upon C. sexguttata. 
A. Syncytia 
The anterior end of each bipartite testis is a loosely arranged 
tubular coil containing early spermatogonial cells. The young- 
est of these are crowded with cells having no perceptible cell 
wall (figs. 5, 6, and 7); the wide internuclear protoplasmic spaces 
are homogeneous save for a few scattered unknown chromatin 
staining bodies (figs. 5, 6, and 7). As the cells further mature, 
light streaks may occur here and there in the cytoplasm, appear- 
ing as cytoplasmic fibrillar bridges. With the increase in age 
and size of the cells, these bridges become more dense and as- 
sume a definite arrangement about a number of cells. This 
continues until the entire tubule is subdivided into a large num- 
ber of syncytia—cysts containing cells without perceptible cell 
walls. 
Wieman (710) presents a study of the cyst formation in one of 
the Chrysomelid beetles, Leptinotarsa signaticollis,.in which he 
concludes that the process is carried on by amitotic cells multi- 
plication. He says: ‘‘At any rate, in the earliest stage at which 
the cysts can be recognized, they are filled with cells undergoing 
amitosis.”” Disregarding the controversy over amitotic divi- 
sions in the primordial germ cells, the fact that such divisions 
were found in the cyst when it is first recognizable, does not seem 
to justify the conclusion that these cells are fundamentally con- 
cerned in cyst formation. No such cell divisions were found 
in the formation of the testicular syncytia of the tiger beetles. 
In the stage represented in figures 5, 6, and 7 the syncytia are 
somewhat elongated, and contain from five to eight giant nuclei 
in cross-section or a total of from twenty to thirty nuclei. 
