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[Vol. 91 
interval. Ants originally marked while convening now appeared to do 
foraging instead. Ants marked while doing midden work now did 
convening, as did those marked while foraging. Finally, ants marked 
while doing nest maintenance now tended to do patrolling. These 
results are summarized in Table 2C. 
D. Behavior of callow workers. The two-way chi-squared test on 
the data on callow workers shows that the ratio of callows to other 
ants depends highly significantly on activity (p < 0.0001). In both 
colonies in which callows were observed, the callows were most often 
observed convening. 
Callows that were marked while convening and observed for 35 
days were significantly likely to continue to convene (p < 0.0001 for 
two-way chi-squared test, p < 0.00 1 for two-by-two chi-squared test) 
(Table 2D). Although dark-pigmented, older ants marked while con- 
vening were also likely to do midden work during the first 35 days 
(Table 2A), it appears that convening callows were not likely to do 
midden work (Table 2D). 
The results of these two procedures show that callow ants convene 
for at least 35 days. Although in the field P. badius callows acquire 
darker, adult coloration within 25 days (Gentry 1974), only 6 of the 20 
callows marked while convening were as dark as non-callow adults at 
the end of 40 days. The others were still of intermediate coloration. 
E. Body size. There was no significant relationship between 
head width and type of activity in minor workers. The two-way anova 
showed no interaction between colony of origin and type of activity 
(DF = 24, SS = 0.44, F = 0.64, p> 0.8993), no effect of type of activity 
on head width (DF = 4, SS = 0.09, F = 0.77, p > 0.5492), and a 
significant effect of colony of origin on head width (DF = 6, SS = 
1 .30, F = 7.53, p> 0.001 ). Mean head size for all 25 workers in all five 
activities ranged from 1 .53 mm in one colony to 1 .78 mm in another 
of the seven colonies. Mean worker size increases with colony age 
(Oster and Wilson 1978). Differences in age among the seven colonies 
probably account for the effect of colony of origin on head width. 
Discussion 
At any one time, exterior workers in the P. badius colony can be 
divided into four groups that consistently perform certain roles for at 
least 35 days: 1 ) midden work and patrolling, 2) nest maintenance, 3) 
foraging, and 4) convening. 
