1963] 
Creighton — Cryptocerus texanus 
137 
gust must displace some of the foraging workers of a free nest. The 
victims of such accidents undoubtedly return to the nest but to do 
so they have to traverse the ground at the base of the tree. It is easy 
to interpret this action as the return of a forager which, in a sense, 
it is. But when workers of texanus are found wandering on the 
ground at the base of a tree this does not constitute proof that the 
foraging has been terrestrial. The writer fell into this trap in 1954, 
for at that time it was not considered that the presence of texanus 
workers on the ground below a tree might be accidental. 
While the nests in the aquaria showed many advantages they had 
one serious defect. It was impossible to see what was going on in the 
burrows. There seemed to be no reason why this defect might not be 
remedied if the ants could be made to accept “burrows” in which one 
side was closed with glass. Accordingly, small blocks of seasoned oak 
10.5 x 3.5 x 2.5 cm were secured. A shallow groove about 7 cm. 
long was cut on one side of the block and at one end of this groove a 
hole was drilled to the opposite side of the block. By using a drill 3/3 2 
of an inch (2.38 mm.) in diameter and by drilling at an angle to the 
surface, an oval nest opening 2.75 x 2.50 mm. was produced. While 
this was slightly smaller than the natural nest entrance, the size dif- 
ference caused the ants no difficulty. After the oak block had been 
drilled the face with the “burrow” was placed against the front pane 
of the aquarium and the block was held in this position by a rim of 
paraffin. Light was excluded from the “burrow” by a piece of card- 
board taped on the outside of the glass opposite the oak block. The 
ants had access to the “burrow” through the drilled hole which opened 
into the aquarium. The ants were much more hesitant to accept these 
passages than those in branches. In order to get them to enter the 
passage it was usually necessary to chill some members of the group 
to immobility and insert them through the nest opening. If the 
opening was plugged for several hours thereafter the workers inside 
the passage became accustomed to it and on their release would lead 
the remainder of the group into the passage. Once the ants had estab- 
lished themselves in the passage they seemed thoroughly satisfied with 
it. Some of the ants lived in the oak blocks for months. 
One surprising fact was apparent as soon as the colony had estab- 
lished itself in the passage. Although the length of the passage was 
about 7 cm., the ants preferred to pack themselves tightly into the 
outer half of it. They would rarely go into the inner half of the 
passage and they would never stay there. As far as motility is con- 
cerned this packing is very awkward, for only individuals at either 
