IO6 



CHARLES V. MORRILL. 



In Fig. 10, a-//, are shown eight 21 -chromosome groups. Fig. 

 10, a, is from an early cleavage stage corresponding approxi- 

 mately to the fourth cleavage of holoblastic eggs. 13 Fig. 10, b, c, 

 d, e, and / are from an early blastoderm stage. Seven more 

 perfectly clear counts were made in this embryo, all giving 21 

 chromosomes, making twelve in all. Fig. 10, g and h, are from 

 another embryo in the same stage. Fig. 1 1 shows six of the 22- 

 chromosome groups. Fig. n, a, is taken from an early cleavage 



FIG. ii. Chelinidea villigera. Chromosome-groups of embryonic cells, 22- 

 e, b, c, d and e, from the same embryo; /, from another embryo; 



chromosome type 



a, from an early cleavage 



stage, approximately the fourth. Fig. u, b, c, d and e, are from 

 an early blastoderm stage in which eleven perfectly clear groups 

 were found all with 22 chromosomes. Fig. u,/, is from another 

 early blastoderm. 



As in Anasa, it seems fair to conclude that the embryos with 

 21 chromosomes are males, those with 22 chromosomes, females, 



"After the "second cleavage," the nuclei apparently do not divide quite syn- 

 chronously so that one may find at times an odd number of nuclei, some resting 

 and some in division. 



