1967] 
Creighton — Cryptocerus texanus 
35 
limbs containing colonies of texanus are pulled down the ants at first 
show little tendency to leave them. This suggested that if such limbs 
were wired on another tree at eye-level the ants might remain in them 
and continue their normal activities with the nest positioned so that 
these could be easily observed. 
The first attempt at this had a discouraging outcome. Two days 
after a dead oak limb containing a texanus colony had been wired to 
a low limb of a Texas ebony tree } the ants moved out of the oak 
limb and, taking their brood with them, migrated into the upper part 
of the crown. Since by doing so they removed themselves from any 
possibility of further observation, it can only be conjectured that they 
occupied another burrow well up in the crown of the tree. Much 
better luck was had with two other colonies when the oak limbs in 
which they were living were wired, at eye-level to the branches of a 
grapefruit tree just outside our cottage in La Feria, Texas. This 
arrangement worked admirably, for although the ants explored many 
of the burrows in the tree ? they remained in the oak limbs during 
a six months period of observation. Moreover, an examination of the 
colonies at the end of this time showed that they had done very well 
for themselves, even though living on a tree that is not ordinarily 
utilized as a nest site. Since the principal object of this study was 
to determine whether these colonies behaved differently from captive 
colonies, two control nests were set up in sealed terraria which were 
kept inside of the cottage. 
It was soon clear that the two groups of nests reacted identically 
to light and temperature. Foraging, both in the free colonies and 
the captive colonies, was strictly confined to daylight hours. It would 
occur only when the temperature was 70° F (21 °C) or higher. Be- 
cause of the greater warmth of the cottage the captive colonies usually 
began foraging sooner than the free colonies and the latter would not 
forage at all on cool days. But it was equally clear that the free 
colonies were often restricted to the nest by another factor for, on 
very windy days they would not leave the nest, even though the light 
and temperature conditions were favorable. The foragers from a 
free nest are much more alert than those in sealed terraria. This 
alertness makes them hard to observe since they will usually show an 
avoidance reaction if the observer comes within a foot of them. They 
will move quickly to the opposite side of a leaf or twig or, when on 
large branches they may try to hide under bits of loose bark. But 
there is a much more significant outcome of this alertness for it 
clearly keeps them from being blown out of the tree. The foragers 
cling to leaves with the greatest tenacity when these are moved by 
