138 
Psyche 
[September 
end of the mass can move freely. Those near the middle of the mass 
are usually unable to move at all. When the ants have formed this 
close-packed mass it is difficult to get them to move out of it. Illumina- 
tion with a brilliant spot of light, unless long continued, will do no 
more than make the ants shift position slightly. This packing appears 
to be maintained continuously. For a period of several days the card- 
board covers of the nests were replaced by pieces of red cellophane. 
The ants could thus be observed at any time without exposing them 
to light. Except for the egress and return of foragers the ants remained 
close-packed and quiescent during this entire period. The writer can 
offer no explanation for this behavior but it accords well with what 
has been noted when free colonies are exposed. From the standpoint of 
observation it is unfortunate, for it greatly increases the difficulty of 
keeping a close check on the brood. 
Early in this study it became apparent that few of the feeding 
responses of texanus are normal when the ants are confined in Janet 
nests. Much the same conclusion had been reached in our 1954 study, 
when some of the colonies in Field nests had been kept alive for more 
than a year on a diet of maple syrup or honey mixed with egg yolk. 
But it was obvious that this food could not be obtained under natural 
conditions and equally obvious that the ants had little liking for such 
food even though they could subsist on it. Since no more acceptable 
food had been found, the Janet nests containing the Mathis colony 
were supplied with maple syrup or honey. The ants soon demonstrated 
that they preferred honey to maple syrup and honey became their sus- 
taining diet during a period when they were given as wide a variety 
of small arthropods as could be secured. The arthropods were spider- 
lings, mites, collembolans, newly emerged mantids, nymphal coccids, 
membracids and bugs, termites, small beetles and the larvae of several 
species of arboreal ants. The reaction of the texanus workers to these 
arthropods varied. Some they attacked and cut to pieces, some they 
tried to discard and some they ignored. When the victims were cut to 
pieces the fluids which exuded from them were occasionally imbibed 
by the attacking texanus workers. But as soon as the victim had been 
immobilized or killed they rarely paid any further attention to it. 
This behavior was so strikingly different from that shown by most 
entomophagous species that, even admitting that it may have been 
abnormal, there was nothing about it to suggest that arthropods form 
a part of the diet of texanus. On the other hand this behavior could 
readily be regarded as a defense response which would rid the nest 
