132 
Psyche 
[September 
After observing the raid for about an hour, I excavated 
the fusca nest in part. My efforts were clumsy, and I suc- 
ceeded only in turning up a few workers and blocking the 
main entrance galleries. But at this point the role of the 
neorufibarbis was revealed, for as soon as I buried the 
access to the nest, they joined in with the ivheeleri workers 
to dig it out again. There was no hesitation in this act, 
despite the fact that they did not follow through to join 
in the actual pillaging. 
The raid continued through the remainder of the after- 
noon, the intensity of activity fluctuating as from time to 
time the number of workers issuing from the home nest 
rose and then fell again. After 4:00 the raid against 
the lasioides began to slacken, and by 5:15 it had ceased 
altogether. By 5:30 activity around the fusca nest was 
also noticeably less. 
When the raid had fallen into an obvious decline, around 
5:30, I proceeded to excavate the ivheeleri home nest. The 
exterior consisted of a low, oblong earthern mound about 
two-and-a-half feet in maximum length and three inches 
high. Sparse tufts of grass emerged through the periphery, 
at one end sheltering three inconspicuous entrance holes. 
By digging a pit four feet deep in from the side, I un- 
covered the deepest galleries of the nest at about three- 
and-a-half feet. Inside the nest the ivheeleri were out- 
numbered by their slaves by at least three to two, while 
the neorufibarbis and fusca occurred in approximately equal 
numbers. No lasioicles were encountered, despite the fact 
that the ivheeleri had been engaged in a raid against a 
nest of this species earlier in the day. The upper galleries 
and chambers of the nest contained large numbers of 
ivheeleri and neorufibarbis and a few small individuals of 
fusca. The former two species sallied out aggressively 
to defend the nest. The deeper galleries, those at a depth 
of about two feet or more, were larger in size and packed 
with large fusca workers, ivheeleri brood, callow ivheeleri 
queens (a single fully colored male was also found), and 
a small number of ivheeleri and neorufibarbis workers. 
The fusca workers were relatively docile, and nearly all 
were in a semi-replete condition. Their preponderance 
