6 BULLETIX 1349, IT. S. DEPARTMENT OE AGBICHLTDBE 
mimrauni. although in any event, in the cooler weather of spring or 
fall, there are few frames containing sealed brood. The hive being 
open for so little time, danger from robbing is also reduced, and the 
normal activity of the colony is disturbed to a far less degree than 
is the case in any other method of brood-area determination so far 
employed. The great speed with which the work can be accomplished 
adapts this method to investigations on a large scale. In the first 
two years of this work more than IS, 000 pictures were thus taken. 
DEFINITIONS 
The term " brood nest" as used in this bulletin applies to the space 
occupied by brood, regardless of the number of hive bodies in which 
brood is found. The term tl : brood area" is similarly applied. The 
term "super" is used for the hive bodies which are placed above 
the second hive body to give additional room for colony activity, 
the lower two hive bodies being those which remain with the colony 
permanently, summer and winter. The hive bodies are of uniform 
size, regardless of purpose. Brood could be reared in the supers of 
hives in which no restriction was placed on the movements of the 
queen by a queen excluder. In the apiary of the Bureau of En- 
tomology, where this work was done, the colonies are arranged in 
groups of four for convenience in putting them into packing cases 
for winter, and such groups are referred to as packing-case groups. 
The term "quadruple packing case" refers, of course, to the fact 
that each of the packing cases used is capable of containing four 
colonies. " Xectar flow" and ''honey flow" are used synonymously 
to cover those periods in which nectar available for the honeybee is 
secreted freely. "Pollen yield" refers to the gathering of pollen in 
large quantities. The term "natural requeening" is used in this 
bulletin for the requeening of colonies in which it is impossible to 
determine whether the old queen was lost through natural superse- 
dure or whether she was accidentally killed while the colony was 
being handled. Where artificial requeening was practiced, as by 
the filling of the old queen and the giving of a queen or queen cell, 
the period of queenlessness is less than in natural requeening. 
ANNUAL BROOD-REARING CYCLE 
Common recognition of certain factors underlying brood rearing 
has given rise to different apiary practices. For example, it has long 
been believed, regardless of geographical conditions, that a honey 
flow greatly stimulates egg laying. This is attested by such apiary 
practices as dequeening during a honey flow, removing brood, and 
the like. Although apiary practice has contributed much to a 
knowledge of brood rearing, it has not as yet furnished a clear, 
definite understanding of all of the factors causing an increase or 
decrease of brood-rearing activity. For instance, it has not been 
established as a fact that brood-rearing activity increases in a uni- 
form and regular manner during the beginning of the active season, 
nor that irregularities may then occur. In short, each seasonal 
phase of brood rearing presents problems, not fully solved as yet. 
which are of vital importance in beekeeping practice. 
It is a matter of common apiary experience that during a certain 
portion of the year, depending on weather, nectar flows, and other 
