362 ROBERT H. BOWEN. 



PLATE II. 



Fig. 30 is from Eitschistits servus ; Figs. 17, 23 and 24 are from Euschistus 

 euschlstoides ; Figs. 18 to 21, 28 and 31 are from Brochymena quadripustu- 

 lata; the others are from Murgantia histrionica. All the figures are from 

 cells of the small ("normal") generations except 23, 24, 30 and 35. 



FIG. 17. First maturation division telophase. Division of the mitochon- 

 drial "palisade" practically complete. (Benda.) 



FIG. 18. Second maturation division telophase. (Modified Kopsch.) 



FIGS. 19, 20, 21. Spermatids. Progressive stages in the aggregation of the 

 Golgi elements to form the acroblast. (Modified Kopsch.) 



FIG. 22. Spermatid. Centrioles double, and the tail filament in first stage 

 of its growth. (Benda.) 



FIG. 23. Spermatid. First appearance of the vesicular acrosome within 

 the acroblast. (Modified Kopsch.) 



FIG. 24. Spermatid. Later stage- in the differentiation of the acrosome. 

 (Modified Kopsch.) 



FIG. 25. Spermatid. Nebenkern halves elongating; typical granule devel- 

 oped in the acrosome. (Benda.) 



FIG. 26. Spermatid. Centrioles in "V" formation. (Flemming-hematoxylin.) 



FIG. 27. Spermatid. First steps in formation of swellings on the mito- 

 chondrial sheaths. (Benda.) 



FIG. 28. Spermatid. Late stage in differentiation of the acrosome. (Modi- 

 fied Kopsch.) 



FIG. 29. Spermatid. Pseudo-blepharoplast completely formed ; centrioles 

 straightened out along the main axis of the sperm. (Flemming-hematoxylin.) 



FIGS. 30, 31. Spermatids. Final steps in separation of the acrosome from 

 the acroblast (Golgi remnant). (Modified Kopsch.) 



FIG. 32. Spermatid. Head and portion of the tail with the characteristic 

 swellings on the mitochondrial sheaths. (Benda.) 



FIG. 33. Immature sperm head. The chromatin forms a thin axial rod 

 enclosed in a protoplasmic envelop. (Flemming-hematoxylin.) 



FIG. 34. Mature sperm head from small cell generation. (Flemming- 

 hematoxylin.) 



FIG. 35. Mature sperm head from large cell generation. (Hermann- 

 hematoxylin.) 



