1927 ] 
The Slave Raids of Harpagoxenus americanus 
19 
At 1:37 P. M. the Harpagoxenus entered the little cavity 
in which the Leptothorax had placed their brood. Thirty seconds 
later the curvispinosus queen came hastily out and ran to the 
opposite end of the nest. After another thirty seconds a cur- 
vispinosus worker emerged with a pupa. This worker was fol- 
lowed by the Harpagoxenus for a short distance, but the latter 
quickly returned to the cavity. One minute later it appeared in 
the entrance to the cavity with a Leptothorax worker in its man- 
dibles. This it dropped outside the cavity and immediately 
reentered. A general distrubance now pervaded the Leptothorax. 
An exodus of those in the cavity, many of them carrying pupae, 
was followed by a spread of the excitement to the workers in 
the nest, who ran about in a confused and terrified manner. A 
few bold individuals remained at the entrance of the cavity and 
two ventured inside long enough for each to recover a pupa. A 
third worker who attempted to enter was apparently seized by 
the Harpagoxenus, for it disappeared into the cavity with startling 
suddenness and did not come out again. 
At 2:00 P. M. the Harpagoxenus began a series of manouvers 
which can best be described as “reconnoitering.”. At first it 
thrust only its head out of the entrance of the cavity and waved 
its antennae about. At such times any curvispinosus near the 
cavitjr rushed away as though in terror. After about forty 
minutes of this behavior, it began making short sorties from the 
cavity. At first it hardly more than emerged, returning at once, 
but after twenty minutes it began to extend its reconnoiters. 
Twice during these sorties the Harpagoxenus attacked and injured 
a curvispinosus worker. In both cases this was done in a delibe- 
rate and spiritless manner. Most of the curvispinosus workers 
who chanced to encounter the intruder ran from it and were not 
attacked. When it left the cavity at 3:40 a change seemed to 
come over the Harpagoxenus. It no longer lumbered about the 
nest in its customary manner. Its movements were quick and 
active. During the next thirty-two minutes the Harpagoxenus 
attacked and injured eight curvispinosus workers with a ruth- 
lessness and a “mordlust” that would have done credit to 
Polyergus. The victims were bitten in the thorax and abdomen 
and left in a dying condition on the floor of the nest. Twice 
