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females in the remaining families as compared with the workers, larvK, 
and pupae, can not be explained without a better knowledge of the 
economy of this species. It will be noticed that the fully developed 
nests, that is, those containing ants in the various stages due at this 
season of the year, vary in number from 655 to 1434. with an average 
for the 17 larger nests of 979. 
It is probable that families reach their largest size in grass-lands, 
where they may multiply without disturbance year after year ; and 
consistently with this supposition Mr. Kelly found in following the 
plow in a field of grass in April, 1906, some of the largest nests of 
our record. In one nest were nearly 6000 larvae and 300 workers, 
with no eggs, no pupae, and no queen. Thirty-nine other nests in this 
field were seemingly as large as this. 
Intercolonial Hostilities 
The well-known but remarkable hostility of ants of one colony to 
those of another of their own species is well illustrated by many of the 
observations of my field and laboratory assistants. 
For example, the first of April, 1906, a strange queen introduced 
to a group of some forty workers of the corn-field ant confined in a 
formicary, was ruthlessly attacked and killed by them as an intruder. 
Precisely the same observation was made in another case April 27. 
August 15, 1905, a wandering lone queen placed in a formicary 
inclosure with five males from another locality killed two of them 
the same day. During the following night two stray worker ants of 
her species entered the formicary thru a crevice and attacked the 
queen, one of them seizing her foot with its mandibles and holding 
fast for an hour and a half, when, as it could not be compelled to 
release the queen, it was killed to save her. 
August 16, 1905, a strange male was first placed among twenty 
workers in a formicary, but being instantly attacked it was transferred 
to another containing only a lone queen — one who having rid herself 
of her wings was presumably already fertilized. The male being dead 
in the morning, the presumption is strong that the queen killed it. In 
another case, occurring August 15, four males placed in the nest with 
a strange queen were immediately attacked by her, and two of them 
were presently killed. On the other hand, a queen ant still bearing her 
wings, placed alone with a strange male August 21, made friends 
with him immediately. The two continued to live in harmony, the 
queen sometimes caressing the male and even apparently feeding him, 
until the 26th, when she began to try to pull off her wings and refused 
to have anything further to do with the male. September 6, altho still 
bearing her wings, having failed in her efforts to remove them, she 
began to lay eggs. This seems a possible case of fertilization of the 
queen within the formicary, but direct observations to that effect are 
wanting. 
August 16, a male from one formicary put in with the workers of 
another was immediately pounced upon by them, and would evidently 
have been killed if he had not been promptly rescued. 
