66 
Psyche 
[June 
is noteworthy. Other common ants of the area that had 
a comparable colony size had a varied myrmecophilous 
fauna. Two phorid flies hovered over the nest while the 
brood collection of April 27 was being made and one 
apparently tried to ovoposit on a worker but both soon 
left. The integument was probably too dense for these 
parasites. On May 21 five workers were found in a motion- 
less mass at the base of the tree under their nest. They 
were placed in a moist container to determine whether 
parasites would emerge but none did. 
The marine toad, as noted before, fed on these ants 
and was the only predator observed. The stomachs of 
several ant-eaters (Tamandua longicaudata and Cyclopes 
pygmaeus ) , taken from nearby trees, did not contain re- 
mains of these ants. 
General Behavior 
The behavior of the workers underwent a marked change 
during the months of observation and collecting and seem- 
ingly as a result of this “persecution.” At first they were 
aggressive, swarming over the hands and biting repeatedly. 
Their small mandibles could only pinch the human epider- 
mis. Some workers fled but none freely dropped off the 
tree. Those which dropped off to the ladder or the clothes 
immediately climbed to where they could bite the exposed 
skin. 
During July and early August they lost their aggressive- 
ness to a large extent. By this time there were much fewer 
individuals and stimulation of one another would be re- 
duced. Nevertheless, when a mass of workers would be 
encountered, as in exposing an auxiliary nest, the ants 
seldom attacked but fled. 
By September the ants were so timid that, when one 
would be approached, it would instantly release its hold 
on the branch and drop to the ground from any height. 
It was noteworthy how often in their fall they might catch 
hold with their tarsal claws of a leaf, twig or hair on 
one’s arm as they brushed by. The ants freely dropped 
off though one’s fingers might be 15 cm. from them. Those 
that did not drop off ran quickly to the underside of the 
