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As soon as the first drone oomb is well filled, emother drone oonb 
is substituted for one of the brood combs. This is usually about a week 
or 10 days after the queen has ooamenoed laying. After another week or 
10 days the first drone comb is removed to a drone nursery colony and re- 
placed with a third drone comb. In this way sometimee three or four drone 
combs can be filled within a month after laying starts. 
Special precautions are taken to prevent strange yellow bees, which 
might develop into laying workers, from drifting into the drone-rearing 
colony. The colony is established at least 100 yards away from the queen- 
yard and frequent examinations are made to find and kill any yellow bees 
that might have drifted in. If other drone— rearing colonies are kept 
near by, they are removed before yellow bees begin to fly from them. 
The drone nursery colony is placed in or very near the queen yard, 
so that drones from it are conveniently available for insemination. It 
is kept separated from other bees as much as possible to prevent drifting 
in of yellow bees* A l-story 10-frame standard hive is provided with 5 or 
6 combs of brood and 4 pounds of bees of black stock, added from a screen 
cage through an excluder, together with some honey and a great excess of 
pollen. The bees are confined for 2 days, A screen top is placed under 
the cover, so that ventilation can be provided by lifting the cover slight- 
ly when the excluder at the entrance becomes crowded with drones trying to 
get out. The bees rear their own queen, which remains a virgin because 
she cannot get out of the hive to mate • Her presence prevents the develop- 
ment of laying workers. More brood is added later to provide a continual 
supply of young bees. 
If the nursery colony is so situated that yellow bees drift in, the 
drone combs are removed after 24 days, and all other drone brood is killed 
at 10-day intervals. These precautions are taken to prevent sons of lay- 
ing workers from maturing, and are unnecessary when the entire worker 
population is of a body color distinguishable from the drones being nursed 
by the colony. 
All manipulations of the nursery colony are made early in the morning 
while drones are not normally flying. OfteA it is necessary to work the 
colony in a portable screen cage to prevent stray drones from drifting in. 
After long confinement or when the presence of excluders has kept them 
out of the hives during the night, drones will often fly in the morning. 
The screening of bees for rearing and nursery colonies serves two 
purposes. It eliminates superfluous black drones which would crowd entrances 
unnecessarily and also prevents the accidental addition of a queen. For 
these reasons the procedure has become a matter of routine not only in 
stocking these colonies but also in stocking nuclei. 
At the age of 8 days drones become sexually mature and try to leave 
the hive* At this age the maximum number of sperms has accxanulated in the 
seminal vesicles, but the drones often do not ejaculate well until they have 
been trying to get out for a nximber of days. The feces that accumulate 
