358 H. HONDA. 



cells. Since many spermatids are produced in the cysts, if they 

 move to the sustentacular cells through the tails of other sper- 

 matids, they meet much resistance; they, therefore, might be un- 

 able to reach the cells. 



The most conspicuous difference between the case of Stomaphis 

 yanois and that of these aphids is the position of the retrogress- 

 ing spermatids. In the former case the smaller spermatids ap- 

 proach the sustentacular cells, and then gradually retreat toward 

 the tails of the larger spermatids ; their position, consequently, is 

 regular, having a relation to the development of the larger sper- 

 matids. In the latter case, however, the position of the retro- 

 gressing spermatids is irregular. 



As in the case of Stomaphis yanois retrogressed spherical cells 

 are seen in the cyst with fully developed spermatozoa. These 

 cells attach themselves to the epithelium of the cysts and have the 

 same fate as the retrogressed cells of the smaller spermatids of 

 Stomaphis yanois. 



V. REVIEW. 



According to Meves and others, one of the secondary sperma- 

 tocytes of the honey bee is much smaller than the other, and re- 

 ceives no chromosomes ; it, consequently, degenerates after some 

 time. The larger secondary spermatocyte, moreover, divides 

 unequally in the second spermatocyte division. The chromo- 

 somes divide this time, and there are produced larger and smaller 

 spermatids. The larger spermatids differentiate into functional 

 spermatozoa. The smaller spermatids also undergo some differ- 

 entiation which, however, comes to a standstill at a late stage 

 and then they degenerate without transforming into functional 

 spermatozoa. The smaller spermatid of Stomaphis yanois re- 

 sembles that of the honey bee in some respects. Both of them are 

 much smaller than the larger spermatids, but judging from the 

 Meves' drawings, the difference in size between the larger and 

 the smaller spermatids is greater in the honey bee than in the 

 aphid. They both develop to some extent, but do not transform 

 into functional spermatozoa. Meves does not state what kind 

 of changes occurs in the degenerating smaller spermatids of the 

 honey bee ; I am, therefore, unable to compare their later stages 

 with those of the smaller spgrmatids of Stomaphis yanois. 



