STUDIES ON INSECT SPERMATOGENESIS. 



IV. THE PHENOMENON OF POLYMEGALY IN THE SPERM CELLS 

 OF THE FAMILY PENTATOMIDAE. 



By Robert H. Bowen. 



From the Department of Zoology, Columbia University. 



Received May 6, 1922. Presented by Edmund B. Wilson. 



Introduction. 



In my preliminary "Study" on the formation of the hemipteran 

 sperm (Bowen '20), a summary was given of the occurrence of poly- 

 megalous spermatocytes and sperms in the Family Pcntatomidae, to- 

 gether with a brief statement of the processes by which the poly- 

 megalous sperms are differentiated. It is the purpose of this paper to 

 amplify my original account, thereby concluding the detailed descrip- 

 tion of hemipteran spermiogenesis which was begun in the second and 

 third articles of this series (Bowen '22a and h). 



The material, as indicated by the title, was drawn entirely from 

 Hemiptera belonging to the Family Pentatoviidae. Illustrative mate- 

 rial has been drawn from a great variety of genera; but, as in my 

 second paper (Bowen '22a), the details of sperm formation were 

 worked out only in Murgantia histrionica Hahn, the testes of which 

 were fixed for one hour in strong Flemming and subsequently stained 

 with Fe-hamatoxylin and light green. For studying mature sperms 

 in their entirety, smears were made substantially in accordance with 

 the method of Faust ('13), osmic fumes, Gilson or Bouin being used 

 for fixation, followed by Fe-hematoxylin, sometimes with a counter- 

 stain. In preparing these smears only the vas deferens was used, — 

 a precaution which insures the exclusion of immature sperms. The 

 preparations examined for the occurrence of polymegaly were fixed for 

 the most part in Flemming and stained in Fe-hematoxylin. Wherever 

 possible, the comparisons of various cell elements were carried out on 

 such preparations, but for certain purposes it was necessary to employ 

 special methods which are indicated in the explanatory text accom- 

 panying the figures.^ 



1 For a more complete treatment of technical methods see Bowen '22a; 



