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numbers of marked and unmarked ants observed in each activity, 
during the entire observation period. The latter, two-by-two test used 
the total numbers of marked and unmarked ants observed in the 
tagged activity, and the two summed values for the other four 
activities. 
B. Death rates of marked ants. To determine whether death rate 
differed according to activity, the colony middens were inspected 
daily during the first observation period, and dead marked ants were 
counted. 
C. Continuity of role after a two-month interval. The observa- 
tions described in part A were ended on July 12, 1982. On September 
12, 1982, observations of the same marked individuals in the same 
five colonies were begun again and continued for 25 days, which I call 
the second observation period. A total of 193 observations were 
made, and the data were analysed as before. 
D. Behavior of callow workers. Adult ants that have recently 
emerged from the pupal stage, or callows, are lighter in pigment than 
older adults. Their behavior was examined in two ways. First, for 25 
days during the second observation period, the number of callows in 
each of the five activities was recorded, as well as the numbers of all 
other ants. Records were obtained on only two colonies, since the 
other three colonies had but few callows outside the nest. These data, 
consisting of 8 1 observation records, were analysed as in Part A with 
a two-way chi-squared procedure. This tested whether the distribu- 
tion of the observed number of callows depended significantly on 
activity. 
Second, 20 convening callows in one colony were marked, using 
the procedure described in part A. They were observed for 40 days, 
beginning with the day on which the first group of five callows was 
marked. Convening callows were chosen because it was rare for a 
callow to be seen doing any of the other four activities. A total of 149 
observations were made in this procedure. The data were analysed as 
in parts A and C. 
E. Relation of body size to activity. T o determine whether body 
size is correlated with activity, the head widths of 25 minors in each of 
7 colonies, a total of 175 ants, were measured. Each group of 25 ants 
consisted of 5 ants from each of the five categories of behavior, or 
activities. Head width was measured at right angles to the line 
between the clypeus and occiput, immediately posterior to the eyes. 
