EVEN IF BROUGHT UP SEPARATELY. 147 
cases, amicably received ants bred from its own pup 
but tended by ants from 60, it showed itself fiercely 
hostile to ants from pups born in nest 60, even when 
these had been tended by ants from nest 36. Nest 60, 
again, behaved in a similar manner ; amicably receiving, 
as a general rule, its own young, even when tended 
by ants from 36; and refusing to receive ants born in 
nest 36, even when tended by specimens from nest 60. 
These experiments seem to indicate that ants of the 
same nest do not recognise one another by any pass- 
word. On the other hand, they seem to show that if ants 
are removed from a nest in the pupa-state, tended by 
strangers, and then restored, some at least of their rela- 
tives are puzzled, and for a time doubt their claim to con- 
sanguinity. I say some, because while strangers under 
the circumstances would have been immediately at- 
tacked, these ants were in every case amicably received 
by the majority of the colony, and it was sometimes 
several hours before they came across one who did not 
recognise them. 
In all these experiments, however, the ants were 
taken from the nest as pupe, and though I did not 
think the fact that they had passed their larval existence 
in the nest could affect the problem, still it might do 
so. I determined therefore to separate a nest before 
the young were born, or even the eggs laid, and then 
ascertain the result. Accordingly I took one of my nests 
of F. fusca, which I began watching on Sept. 13, 1878, 
and which contained two queens, and on February 8, 
