PLATE 6 



EXPLANATION OF FIGURES 



From smear-preparations of Oncopeltus (109-114) and Protenor (115-120); 

 Enlargement 2250 diameters. (X designates the X-chromosome, B the large 

 bivalent in Protenor, m, ?n, the m-chromosomes in the latter form. 



109-114 Middle and late prophases of the first spermatocyte-division, showing 

 various forms of the bivalents during their condensation. In the earlier figures 

 the X-and F-chromosomes are short, longitudinally split rods (109-111) ; in the later 

 ones they are shortening to a dumb-bell form (112-114). Two of the same nuclei 

 are shown in photos. 20, 21. 



115-117 Early prophases (Stage h), the bivalents just emerging from the con- 

 fused stage. The m-chromosomes are but vaguely distinguishable. 



llS-119 Late Stage h, showing all the chromosomes, the bivalents still much 

 diffused. 



120 (photo. 40) Nucleus from Stage i. 



442 



