488 T. H. MORGAN 
The six chromosomes of the female-producing egg appear to 
divide equally, so that the outer and the inner pole of the spin- 
dle get six chromosomes each. 
One point of especial importance I have not been able to settle 
satisfactorily, namely, the fate of the smallest chromosome. The- 
oretically I should expect it to be the lagging chromosome. But 
the figures show the lagging as large as the rest. On the other 
hand it is equally clear that none of the others can be identified 
as the smallest—they appear to be of equal size. The evidence 
is therefore inconclusive either way. If the smallest is the lagging 
it must increase in size before it divides so that its size relations 
are changed. 
THE POLAR SPINDLES IN THE SEXUAL EGG 
Two questions of theoretical interest are involved in the antic- 
ipated reduction in the number of chromosomes in the sexual 
egg of the phylloxerans, namely, the number of the reduced 
chromosomes and their size relations. Whether the reduced 
number would be four or three could not be prophesied from 
the behavior of the chromosomes in the parthenogenetic series, 
for if, as I think, there are two small a-chromosomes attached 
to the two large X’s, the former might separate at the ‘reduction 
period’ to form a smaller pair, giving four chromosomes or else 
remaining attached to the larger X there would appear only 
three chromosomes. Six cases have been found showing clearly 
that the number of chromosomes in the sexual egg is three. I 
have found two eggs that show equatorial plates, figs. 23, 26; 
two eggs that show the chromosomes in the nucleus just before 
its resolution, figs. 27, 28; and two eggs that show side views 
figs. 24,25. There can be no question that the reduced number 
is three. The size relations are more difficult to determine. 
In general it may be said that they are all of nearly the same 
size; although one of them generally appears larger than the other 
two. There is no such disparity in size between the largest 
and the smallest as that observed in the male-producing egg, 
which is a strong argument against my earlier suggestion that 
the smallest chromosome in the equatorial plate of the male- 
