4 
Psyche 
[March - June 
One colony which was baited for five successive days in February 
yielded a total of seventy-seven majors. Moreover, by using bait 
majors were secured from nests which had produced none when dug 
out. For, with one exception, the excavated nests reestablished them- 
selves after a few weeks. This is clear evidence that these nests had 
not been fully exposed. The character of the militicida nest would 
make complete exposure difficult. All the nests that we have encoun- 
tered have been built in light, friable soil between large stones. As 
these stones are removed the soil between them crumbles away and this 
obliterates any passages that were in it. As a result it is usually 
impossible to follow the passages to any depth and as excavation pro- 
ceeds there is not the slightest indication of the direction it should 
take. In our opinion no nest of militicida has yet been completely 
excavated. 
In areas where militicida is abundant there are often places where 
several nest entrances are close together. The distance between the 
entrances will vary from two to eight feet. It seems impossible 
at present to state whether each entrance represents a separate nest or 
whether they all belong to a single elongated nest. The total nest 
count given in this paper (15) is based upon the latter supposition. 
The total number of entrances found is five or six times greater. It 
was soon found that majors and minors from entrances a few feet 
apart could be mixed together without showing any signs of animosity. 
At first we accepted this as positive proof that the several entrances 
all belonged to one nest. But later the disconcerting fact came to 
light that the same result could be secured with specimens from 
nests a half a mile or more apart. The only explanation that would 
seem to fit this surprising behavior is that militicida is almost totally 
devoid of inter-colony animosity. The situation is made even more 
inexplicable by the strong animosity which militicida exhibits toward 
other species of ants. 
We expected militicida to forage sporadically during the winter 
but it was a surprise to discover that it is one of the most consistent 
winter foragers in the area where it occurs. The only other ant 
which shows comparable activity is Myrmecocystus mimicus Wh. 
Except for one or two days when rain or snow fell, the minors of 
militicida were out every day during January, February and early 
March. As a rule the foraging did not begin until 3 :oo P. M. By 
that time the surface temperature had reached 6o°F. (i6°C.) or 
better. Full foraging activity developed when the surface temperature 
reached 90°F. (3i°C.). During January the surface temperature 
