28 BULLETIN 1222, U. S. DEPARTMENT OF AGRICULTURE. 
INSPECTION, TYPE B. 
On other occasions a nurse bee approaches an open brood-cell, 
pauses, lowers her head and thrusts it into the cell, but withdraws 
it almost immediately. The whole head may be thrust within the 
cell and perhaps part of the thorax as well. When the whole time 
of this operation does not exceed two seconds, it is assumed that there 
is not time for the nurse bee to do anything in the nature of actual 
feeding. Two seconds might allow time for the ejection of a liquid 
food, but such a short time is probably insufficient for a determina- 
tion of the already available food supply or the needs of the larva 
and then additional time for supplying such food as may be needed. 
In taking data on the time spent in caring for the brood, all such 
activities are designated Inspection, Type B. That bees do determine 
the quantity of food present is evidenced by the fact that all larvae 
of approximately the same age and position on the comb have about 
the same amount of food at all times. This would not be the case if 
the different nurse bees did feeding indiscriminately and without a 
determination of the amount of food already within the cell. There 
is opportunity in the form of activity under this heading for tactual 
contact with the larva, while in the former type (Type A) there is 
no such opportunity. 
NURSING. 
Feeding of the larva occurs when the nurse bee enters the cell, but 
obviously an appreciable time is required for this activity. For such 
activity the descriptions under the two preceding types of inspection 
are not valid. While the nurse bee is within the cell, activities other 
than actual feeding may occupy part of her time, but probably all 
these activities have to do with the care of the larva. 2 
The time spent by a nurse bee within the cell engaged in feeding 
varies betAveen 2 seconds and from 3 to 4 minutes. Even the shortest 
periods may be distinguished from inspection by the fact that there 
is a noticeable pause of the bee while within the cell. The longest 
periods mentioned are quite exceptional. It is impossible to see what 
a nurse bee is actually doing within a cell, but some basis for a 
differentiation between inspecting and nursing visits should be 
adopted, even though it appears more or less arbitrary. The most 
practical basis appears to be that of time. When the time spent 
within the cell is less than 2 seconds the visit is classed as an in- 
spection, and when the visit is of longer duration it is considered 
under the designation nursing. This basis does not appear so arbi- 
trary to the observer, since the actual behavior in these two cases 
appears rather more distinctive than the difference in time alone 
would cause one to believe. While it is quite possible that occa- 
sionally an inspecting bee may spend more than two seconds, it is 
nevertheless true that most inspection visits are completed in less 
than two seconds. 
Having, therefore, decided upon this method of classification of 
the behavior of the nurse bees, observations were begun. The results 
2 Occasionally a worker bee creeps into a brood-cell containing a small larva merely to 
rest. Sucb a worker may usually be distinguished promptly from a nurse bee engaged 
in ber duties of feeding. 
