Sex Determination in Phylloxerans and Aphids 297 
(Fig. XLX, Q, R, S). Whether the size differences that appear 
are significant [ cannot state as yet. The somatic cells of embryos 
from these eggs (artificially obtained) showalso eight chromosomes. 
In P. globosum, the polar plates contain six chromosomes (Fig. 
XIX, K—N) but in this case they are not rounded but elongated. 
Their bent form renders a study of their size relations difficult. 
Oe % 
. ee 9° & 
yt 
A B a 
E 
*e 
e a oe 
eee of cet ose = 
%@ Se. 
C0 @s350 MV c008 
F °e® e@ I 
G H 
Gg K L M a 
a 
° 
oe o° 93 
O iP Q R S 
Fig. XIX A-F, equatorial plates of polar spindles of egg of migrant of P. subelliptica; G, H, ditto 
of caryeglobuli; I, equatorial plate of polar spindle of egg of stem-mother of P. depressa; 7, late 
egg-nucleus of same; K, L, M, equatorial plate of polar spindles of egg of migrant of P. globosum; N, 
equatorial plates of polar spindle of stem-mother’s egg of same; O, P, late egg-nucleus of same; Q, R, 
S, equatorial plate of polar spindle of egg of migrant of P. caryefolie. None of the figures drawn to 
scale. 
