296 ELIZABETH A. SMITH. 



PLATE III. 



Sympterum semicinctum (Say). 



FIGS. 21, 22 AND 23. Leptotene threads forming from the masses. In 22 and 

 23 the sex-chromosome is present. 



FIGS. 24 ( X 3,900), 25 AND 26. Synaptic stages in which parallel leptotene 

 threads unite. 



FIGS. 27, 28 AND 29. Synizesis stages. 



FIGS. 30 AND 31. Polar views of cut threads of a stage like Fig. 29. 



FIGS. 32 AND 33. Chiasmas. 



FIG. 34. Threads opened out into apparent eights. 



FIG. 35. A true eight. 



FIG. 36. A cell of Anax junius which shows chromomeres in the segments. 



FIG. 37. Cell with signet-ring loop. 



FIG. 38. Signet-ring loop from several angles. 



FIGS. 39, 40 AND 41. Contain prophase crosses. Fig. 40 shows the sex- 

 chromosome and Fig. 41 contains the largest cross. 



FIGS. 42, 43 AND 44. Polar views of the chromosomes of the primary spermato- 

 cyte division. 



