WENKICH: spermatogenesis of PHRYNOTETTIX MAGNUS. 83 



size can frequently be noticed throughout the pachytene stages. 

 Examples of this may be seen at b, e, i, I, and o in figure 98 (Plate 8), 

 which are drawn from the same individual as figure 58. Similar 

 conditions are also to be found in other individuals, as will be seen in 

 figure 97,. a, c, e, j, and /. 



This pair of chromosomes can be recognized in the spermatogonia 

 by the presence, in the telophase, of the three most prominent granules, 

 those I have numbered 1, 4, and 5 in the pachytene stages. Examples 

 of such telophases are represented in figures 87-96. In two cases, 

 where the cliromosomes had become considerably elongated in the 

 general diffusion process of the telophase, I was able to make out 

 granules 2 and 3 also with their characteristic relative positions and 

 sizes. These are shown in figures 95 and 96. Where both chromo- 

 somes of the pair are recognizable in the same nucleus, there seems to 

 be in every case a difference in size between the two middle granules 

 (no. 4). This difference is probably directly related to the difference 

 noted in the zygotene stage (fig. 58) and the pachytene stages (figs. 97 

 and 98). 



Thus, aside from finding a striking degree of correspondence in the 

 minute organization of the chromosome-pair B for all the individuals 

 studied (in the pachytene stages), it has also been possible to trace the 

 pair through all the stages from the spermatogonia to the spermatid, 

 except in the preleptotene and leptotene stages. Figures 30 (Plate 3) 

 and 58 (Plate 5) show that conjugation is completed at a relatively 

 early stage in the zygotene. This precocious conjugation is possibly 

 facilitated by the relatively small size of this pair. The failure to 

 recognize the pair in the leptotene and immediately preceding stages 

 is probably due to the fact that it has not so great a differential stain- 

 ing capacity as has pair A, and to the lack of sufficiently long con- 

 tinued study with this object in view. 



A further peculiarity of chromosome-pair B may be seen upon an 

 examination of figures 99 and 100 (Plate 9). There it will be seen 

 that one end of the tetrad has a peculiar roughened or brush-like 

 appearance, to which McCIung ('14) has already called attention. 

 It will be noticed in the same drawings that the accessory chromosome 

 also presents a similar appearance. Furthermore, a like condition 

 is to be seen at the longer end of C, as shown in figure 100, and at the 

 end of some of the other autosomes, as seen in figure ^9. The rough- 

 ened contour of the accessory in both metaphase and anaphase of 

 the first spermatocyte division was noted for Phrynotettix by Miss 

 Pinney ('08), and has been described for other species of Orthoptera, 



