14 
There is supposed to exist among the worker bees a division of 
labor, but nothing of the kind has been observed among the keleps, 
except that young individuals, which are easily distinguishable by 
their lighter color, remain in the nest for many days and perform 
nurse duty, while the foraging devolves upon the older and darker- 
colored insects.¢ 
The demoralization of some of our imported colonies may have 
been increased by the lack of a normal succession of young keleps to 
serve as nurses. The predaceous instincts of the older workers may 
incline them not only to neglect the larvae, but to yield more readily 
to the cannibalistic tendency which some of the colonies have mani- 
fested. 
KELEP COLONIES NOT HOSTILE. 
Kelep nests are frequently placed only a few inches apart, the 
workers of the different colonies not being actively hostile. Members 
of two colonies will forage on the same cotton plant or tree trunk 
with no signs of animosity. Stranger ants troduced into captive 
colonies for observation have not been attacked. They usually receive 
little attention; if they enter the burrow they are likely to be brought 
out and carried to the boundary of the inclosure, but are released 
without injury. In nature such stragglers, if any, would merely be 
escorted to the border, as it were. 
Under the social economy of the true ants the species consists of 
fewer and more scattered colonies of larger size. The workers from 
different nests often have as much animosity for each other as for 
members of distinct species. This hostility serves a practical pur- 
pose, the close proximity of nests being, among the ants, a distinct 
disadvantage. It is only in large and prosperous colonies that numer- 
ous sexual adults can be brought to maturity. Too many colonies 
close together would mean a general scarcity of food and would keep 
all the communities poor and unproductive. 
The power of ants to distinguish at once between members of their 
own and of other colonies has long been recognized as one of the most 
remarkable refinements of instinct, and has been the subject of exten- 
sive study and experiment. A recent and extremely careful investi- 
gation has been made by Miss Adele M. Fielde, who finds that the 
«Some species of ants and of termites have a special caste of very small, 
slender workers which do not leave the nest, but are devoted to nurse duty. 
These might be looked upon as representing a social specialization by which the 
microergates are not confined to the first brood. On the other hand the very 
great specialization of the so-called soldier castes of the termites would seem 
to indicate that they are the oldest representatives of the worker series, and this 
view seems to be supported by the fact that the ‘“ workers” of Calotermes, 
which have the simplest social organization, are more like the soldiers of other 
genera than they are like the workers. 
