THE FLIGHT ACTIVITIES OF THE HONEYBEE 25 
days the gathering may not be so great. A comx)arison of the amounts 
of nectar gathered on certain days is not always absolutely indica- 
tive of the amount of nectar available to the bees on these particular 
days. This will be seen clearly from an inspection of Table 1, in 
which are tabulated the total number of returning bees on each 
day" (except when the weight records were disturbed by rain), the 
daily increase in weight of the hive, and the minimum limits of the 
average load carried by each bee on these respective days. The 
average load as given in this table is obtained by dividing the day's 
gain in weight by the total number of returns for the day. Since 
consumption of stores, evaporation of excess water in the nectar, 
and other sources of loss in weight of the hive as a whole are going 
on throughout the day, it is evident that the average loads here com- 
])uted are actually the minimum limits for the average loads carried. 
Other observers have noted that bees sometimes carry larger loads 
of nectar than have been indicated for the best day, judging by the 
total gain of the colony for the day (May 11, 24.1 milligrams), so 
that the figures given in Table 1 are evidently very conservative. 
Throughout the following discussion the expression " average load '' 
refers to these minimum limits. On May 15 slightly less nectar (20 
grams) was gathered than on May 16, yet the average load was 
greater by 1.2 milligrams. The total day's gain was minimized by 
a threatening storm which reduced the number of possible flights. 
Again, on May 22 the load per bee is high (25.3 milligrams), yet 
the total day's gathering is less than on May 20, when the average load 
was 17.5 milligrams. This can be accounted for only by the fact 
that on May 22 some factors were influencing the flights and length- 
ening the average duration of each flight by about 9 minutes (Table 
2), which would in turn reduce the total exits for the day and the 
amount of nectar gathered. 
Without a knowledge of the number of flights which occur, a 
study of the daily gains on May 9 and 24 would indicate that May 
24 was a day of heavier secretion, since more nectar was brought in on 
this day; but a comparison of the total returns and the average 
load per bee shows that the reverse was the case. 
In general. Table 1 shows that although there is a close relation 
between the average load carried by each bee and the daily total, 
the amount of nectar gathered is not necessarily indicative of the 
quantity of nectar available to the bees. The average load per bee 
is the true indicant. 
On six days only — one in April, three in May, one in June, and 
one in July—did the frequency of the flights drop during the hours 
12 m. to 2 p. m., as would be required by the weight curve described 
by Dufour (1) as typical of the spring conditions. On these days 
the drop did not last more than half an hour, and varied in magni- 
tude from 15 to 40 per cent of the average number of exits or returns 
during the main flight for the day. 
THE EFFECT OF HEAVY FLIGHT NEAR BY 
Another colony about 36 feet from the one under experimentation 
was, on May 11, at 2.30 p. m., much disturbed by manipulation, so 
tliat the air in the vicinity was full of flying bees, almost as many 
