Vol. XLII. February, 1922. No. 2 



BIOLOGICAL BULLETIN 



STUDIES ON INSECT SPERMATOGENESIS. III. ON 

 THE STRUCTURE OF THE NEBENKERN IN 

 THE INSECT SPERMATID AND THE ORI- 

 GIN OF NEBENKERN PATTERNS. 



ROBERT H. BOWEN. 

 (From the Department of Zoology, Columbia University.) 



INTRODUCTION. 



In the preceding " Study " of this series I have given a rather 

 full account of the formation of the hemipteran spermatid to- 

 gether with a history of its various components in the subsequent 

 transformation into the mature sperm. An outline of the be- 

 havior of the mitochondria (nebenkern) was included in that ac- 

 count, but it was thought best to postpone any extended considera- 

 tion of details to a later paper. It is the purpose of this paper 

 to complete the description of the nebenkern especially with re- 

 spect to the complicated and fantastic " patterns " which are its 

 chief characteristic in the insect spermatid. 



By the term "pattern," I refer to those curious appearances, 

 which have been likened to a blackberry, an onion, a ball of 

 twine, a skein of yarn, a spireme, and other similar objects, which 

 develop in the nebenkern of the early spermatids and eventually 

 disappear again, It is rather disconcerting to find that after 

 thirty-five years of observation these appearances are not yet 

 understood have never, indeed, been carefully examined as to 

 origin and significance except by Gatenby, whose recent work on 

 the Lepidoptera has served me as a point of departure for this 

 paper. I have not been able to find with certainty who first noted 

 these patterns the early workers seem to have taken them as a 

 matter of course and to have given them no particular emphasis. 



53 



