PLATE 20 



EXPLANATION OF FIGURES 



158a, 158b S. acuticornis. Stage k. Lateral view of spindle and chromosomes 

 in metaphase, similar to figure 157, from two successive sections. Nos. 1, 2 are 

 rods; 3 approaches a ring in shape; 4, 5, 6 and 9 are crosses; 7 and 10, knobbed V's, 

 similar to no. 7, figure 155, or to figure 156; 8 is a view of the distal end of a knobbed 

 ring similar to 10 in figure 155a; 11, side view of a ring similar to figure 156d. 



159 S. acuticornis. Second spermatocyte in metaphase showing the relative 

 lengths of the eleven autosomes. Sex chromosome absent from this cell. All 

 chromosomes are split, though both parts do not always show. 



160 S. acuticornis. Second spermatocyte in metaphase showing twelve 

 chromosomes. The halves of 3, 7, 10, and lOx have begun to separate. 



161 to 187 are from Chorthippus (Stenobothrus) curtipennis Bruner, one of 

 the Truxalinae. 



161, 162 Nuclei of spermatogonia in metaphase. The same size relations 

 appear as in figure 148. The 5's are linked at their proximal ends with the 9's, 

 the 7's with the ll's, and the S's with the lO's. 



318 



