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Psyche 
[Vol. 85 
colonies. However, these behavioral barriers between colonies are 
sometimes imperfect in the case of incipient slave-maker colonies. 
For example, let us consider the situation in Quadrant 3. 
When collected, this quadrant contained two incipient H. ameri- 
canus colonies, each of which was located near an apparently 
unparasitized L. hngispinosus nest. In both cases, some of the 
slaves entered the nearest L. hngispinosus nest without being 
attacked; and, reciprocally, some of the seemingly unenslaved L. 
hngispinosus workers entered the H. americanus nest with impu- 
nity. On one occasion, a slave picked up the H. americanus queen in 
one of the parasite nests and carried her to the nearest L. hngispino- 
sus nest. The arrival of the parasite female caused all the adults in 
that nest to flee. Later the same day, a slave carried the H. america- 
nus queen back to the nest from which she had come. Then, over a 
12-day period, many of the workers which had originally fled moved 
in and began to live peacefully with the H. americanus queen in her 
nest. 
Equally interesting events involved the other incipient parasite 
colony in the same quadrant. A slave which could peacefully enter 
the nearest L. hngispinosus nest began to carry brood and workers 
from that nest into the //. americanus nest. Some of the in-coming 
L. hngispinosus workers were accepted immediately by the other 
slaves, while others were initially attacked. However, after 15 days, 
all the workers from the unparasitized nest were living peacefully 
with the H. americanus queen. A few days later, several L. hngispi- 
nosus workers killed the L. hngispinosus queen which had been 
living in the unparasitized nest. 
Discussion 
Both Wesson (1939) and Alloway (1979) produced slave raids by 
selecting target nests and placing them in arenas with relatively 
populous, single-nest H. americanus colonies. The present study 
was the first in which a broader sample of H. americanus colonies 
has been observed and the first in which H. americanus colonies 
have been observed interacting with other colonies near which the 
slave-makers had been living in nature. These procedural differences 
probably account for the discrepencies between the behavioral 
events observed here and those described by Alloway (1979). Sim- 
ilar procedural differences, combined with possible regional differ- 
