THE BROOD-REARING CYCLE OF THE HONEYBEE 9 
depending on weather conditions; in the one case the force of the 
resulting explosion is definitely predetermined by the quantity of 
the charge; in the other case the amount of brood reared is definitely 
predetermined by the provisions made in the preceding season to 
give the colony the conditions most favorable for this purpose. 
THE MAJOR PERIOD 
The major period of brood-rearing activity extends throughout the 
active season from the time when normally the initial seasonal 
tendency would cease to make itself felt until the beginning of the 
period of final contraction. It is the longest of the three phases of 
seasonal activity. The character and sequence of honey flows under 
different climatic conditions cause brood-rearing activity during this 
phase to vary widely in different regions. Throughout the world, on 
the whole, brood-rearing activity during the major period falls either 
into one of two extreme types or into a gradation between the two. 
During this period one of the extreme types is marked by a con- 
tinuous high rate of brood-rearing activity, while the other extreme 
type is marked by a pronounced slackening or series of slackenings in 
such activity. In the third or intermediate type there is neither a con- 
tinuous high rate of brood-rearing activity during the major period, 
nor under normal conditions is there at any time a complete suspen- 
sion. This intermediate type, however, does show a seasonal slack- 
ening at some time within "the major period. 
A continuous high rate of brood-rearing activity during the major 
period occurs in regions with a long inactive season in winter, fol- 
lowed by a short active season, usually characterized by overlapping 
honey flows. Following the prolonged period of winter suspension 
in such a region, brood-rearing activity during the period of initial 
expansion attains with striking rapidity a high rate, which, unless 
checked by conditions within the hive, is maintained throughout 
the major period extending over practically the whole of a relatively 
short active season and then, owing to the proximity of the period 
of winter suspension, undergoes an abrupt contraction. Such a type 
of seasonal brood-rearing activity during the major period is typical 
of subarctic conditions. 
A more or less complete suspension of brood rearing, or series .of 
such suspensions, is found in regions with a short, almost nonexistent, 
inactive season, followed by a long season of activity, usually charac- 
terized by one or more periods of drought during the hottest weather. 
In such a region the initial expansion in brood rearing does not prog- 
ress so rapidly as in regions with a long, inactive winter season, nor is 
the final contraction so abrupt. The major period,, instead of being 
characterized by a uniformly continued high rate of brood-rearing 
activity, is characterized by a pronounced midsummer slackening, or 
series of slackenings, in brood-rearing activity, probably caused by 
an absence of incoming nectar and pollen during the periods of 
drought. This type of brood-rearing activity during the major period 
is typical of tropical conditions. 
Intermediate between the two types just described is that type of 
seasonal brood-rearing activity which exhibits a more or less marked 
slackening at some time during the major period, but never a com- 
plete suspension under normal conditions. This type may be found 
46969°— 25t— Bull. 1349 2 
