OOGENESIS IN PHILOSAMIA 5 
definite statement is unwarranted, for the chromosomes are so 
small that a slight size difference might easily escape detection; 
moreover the variability in size in different groups, as seen in 
figures 5 and 6 would render any deductions in this respect 
extremely hazardous. 
As the chromosomes approach the ends of the spindle, the 
fibers thicken enormously in the middle, forming a deeply stain- 
ing cell plate, which in side view, gives the appearance of a band 
encircling the spindle (fig. 8). Henking (’92) described similar 
bodies in Pieris, which he considered as waste achromatic sub- 
stance. With long extraction the cell plate appears very faint, 
while the chromosomes remain dark. Figure 9 shows another 
anaphase, in which 13 chromosomes may be counted at each 
pole. No lagging chromosomes were observed. In a late 
anaphase (fig. 10) another size peculiarity is observed, each 
chromosome being after division approximately as large as those 
of the metaphase stage. The irregularity in the form of the 
chromosomes in late anaphase was characteristic of this stage, 
and was equally apparent with either dark or light staining, 
although in the latter case the chromosomes appeared slightly 
smaller. Figure 11 is an oblique polar view of a similar stage; 
on account of the plane of the section the spindle cannot be seen. 
In figures 12 to 14 are shown polar views of spindles, the groups 
lettered a in each case being those entering the first polar body. 
Four chromosomes are in the center of each group, surrounded 
by a ring of nine. The polar body groups sometimes appear 
slightly smoother in outline than the egg groups (fig. 12), smaller, 
and bipartite in preparation for a second division. In attempt- 
ing to compare chromosomes in the polar body with those in a 
similar position in the egg group, it is impossible to obtain any 
evidence either for or against an equal division of chromosomes. 
The variability is extreme, within both egg and polar groups, 
and in many cases it is very difficult to be sure of the actual 
thromosome outlines. 
During the formation of the first polar body the spindle fibers 
elongate considerably, and the granular cytoplasm forms a 
