262 
Psyche 
[Vol. 91 
DEATH 
t 
PATROLLING 
+ — ►CONVENING 
MIDDEN WORK 
A 
FORAGING 
A 
NEST 
MAINTENANCE 
CONVENING 
EMERGENCE 
FROM NEST 
ECLOSION INTO ADULTS 
Fig. I. How role depends on age in exterior workers of P. badius. The vertical 
direction represents worker age. 
35 days, sooner than ants in any of the other groups. It seems that 
convening is done at two different times in the life of P. badius 
individuals. One group of conveners is the youngest group shown, 
because callows are most likely to convene, and continue to do so for 
at least 35 days. The results from the second observation period 
suggest that convening ants become foragers, and some foragers later 
become conveners, as shown. Since marked midden workers did 
convening in the second observation period, an arrow is drawn from 
the patrollingand midden work group to the older convening group. 
There is evidence that this transition may also be made in the opposite 
direction: some ants marked while convening(not callows — see Part 
A) did midden work in the first observation period, and patrolling in 
