312 T. H. Morgan 
workers from workers’ eggs in the American variety of Lasius 
niger. 
These observations make not improbable the view that the 
unfertilized eggs in certain species of ants can produce females, but 
unfortunately we do not know whether two polar bodies are ex- 
truded in such cases. Whether this happens or not, the facts 
indicate that before the extrusion of polar bodies the eggs have the 
dual potency of producing males or females. Such a conclusion 
makes it probable that the bee’s egg too may have the same possi- 
bilities, only here the results are more one-sided, since after extru- 
sion of the polar bodies the resulting egg is male determined. It 
would therefore be erroneous to conclude that the eggs of the 
bee are male before the polar bodies are extruded. 
This case of the honey bee has been one of the greatest stum- 
bling-blocks that modern theories of sex have met. One course in 
avoiding the contradictions here found has been to deny the facts, 
yet the facts seem to me to be as clearly determined as any other 
in this field, and while none of them may be final, yet it is unfor- 
tunate to reject one body of evidence because it does not fit in 
with conclusions derived from the other. 
The unfertilized eggs all develop into males. It is assumed that 
all the eggs are therefore male producing, and thatthesperm brings 
in the female determinant. But there is another theoretical 
possibility. The sex of the egg may not be determined at first. 
lf it is not fertilized, it becomes a male; if fertilized, a female. 
The absence of fertilization or the act of fertilization may be the 
determining factor; or if the result is attributed to something lost 
or retained by the egg, such a result might be referred to the polar 
body formation which responds to the presence or absence of 
the sperm. Such are the difficulties met with on the assumption 
that the sex determinants exist in the egg or sperm or in both.. 
None of these arenecessary if we account for the results on the 
simple assumption that one nucleus means male, two mean female, 
which is the view that I adopted in 1903. 
In another hymenopteron, Nematus ribesii, the facts described 
by Doncaster are so anomalous that at present it is quite impossi- 
ble to bring them into harmony with what takes place in the bee, 
