DAVIS: SPERMATOGENESIS. 75 



the spermatogonia, except that in place of the monosome (4) there is 

 in the oogonia a symmetrical pair. This is in accord with the results 

 of Wilson (:05''), who has shown that in those Hemiptera in which a 

 monosome occurs in the male there is always one more chromosome 

 in the oogonia. Miss Stevens (:08*) has found the same to be true 

 of several Coleoptera. However, Sutton (:02) found only twenty-two 

 chromosomes in the ovarian follicular cells of Brachystola, while in 

 the spermatogonia there are twenty-three chromosomes. 



D. Chortophaga viridifasciata. 



The spermatogonia and apical cell are much as in Dissosteira. In 

 a polar view of the equatorial-plate stage (Fig. E, p. 72) there are 

 also twenty- three chromosomes, of which twenty-two are autosomes, 

 since they can be readily paired. The remaining chromosome (4) 

 is a monosome. I have been unable to find any evidence of a pre- 

 cocious conjugation of the spermatogonial chromosomes such as 

 McClung (:05) found in this species. 



During the prophase of the last spermatogonial division the mono- 

 some can be easily distinguished, since it has a much more ragged 

 outline than the autosomes and lies in a more or less distinct vesicle. 

 In the prophase of the other spermatogonial divisions it cannot be 

 distinguished from the autosomes. 



E. Melanoplus femoratus. 



The testicular elements in Melanoplus are much smaller than in the 

 preceding species, and, therefore, are not in general so favorable for 

 investigation. The primary spermatogonia are much like those of 

 Dissosteira and partially surround the apical cell. On its proximal 

 side this cell is surrounded by connective-tissue cells. The apical 

 cell (Plate 1, Fig. 3), like the other elements of the testis, is much 

 smaller than in Dissosteira and contains no deeply staining granules 

 in the cytoplasm, only the finely granular material which stains lightly 

 with Bordeaux being present. 



The secondary spermatogonia show no essential difference from the 

 same cells in Dissosteira, but the nuclei are even more irregular in 

 shape. During the resting stage, when the chromatin has become 

 most widely diffused through the nucleus, there is often present a 

 deeply staining mass formed by an aggregation of chromatin granules; 

 whether it has any connection with the monosome, I am unable to say. 



