354 Experimental Zoology 
incompatible with Dzierzon’s theorv; yet several explanations 
have been offered to account for these exceptional cases, for 
it is generally admitted that they are exceptional and do not 
represent what usually takes place. 
In the first place, the pedigree of the queen may not have been 
above suspicion, and consequently some of her offspring may 
show traces of their mixed origin. It is said that at the present 
time the domesticated races of bees have been so often crossed 
that it is difficult to obtain a pure individual. In any particular 
instance the matter could be easily tested by rearing sister queens 
of the same brood, crossing one and breeding the other true. 
This simple test does not appear to have been made. 
In the second place, the hybrid drones may have come from 
the hybrid workers that sometimes lay eggs, rarely in the com- 
mon hive bees, but more often in the Syrian and Palestine races. 
In the third place, it has been found that Italian bees of presum- 
ably pure stock often produce drones that are very variable in 
their markings. In a recent paper by Casteel and Phillips it 
has been pointed out that the males are often more variable than 
the workers — a fact of much biological interest in itself, aside 
from the present question, since it shows that variation is not 
necessarily connected with the union of two germ-cells from 
different individuals, as Weismann and his school have assumed. 
In another way Dzierzon’s theory was tested, and apparently 
found wanting. Landois (1867) put worker eggs into drone 
cells, and drones were produced. Conversely he put drone eggs 
into worker cells and workers were produced. The real expla- 
nation of this result is, however, not that the kind of cell de- 
termines the sex of the individual, as the experiment seemed to 
show, but that the bees themselves often clean out a cell into 
which an egg has been introduced, perhaps because of the 
imperfect method of fixation of the egg, and subsequently the 
queen will deposit the proper kind of egg in the cell. Thus 
the bees themselves easily defeated the purpose of the experi- 
ment. The experiment could be properly carried out by 
removing the queen when the transfer is made, so that no 
