66 
Psyche 
[June 
representing another colony, was encountered between 200 and 300 
meters from the cave entrance. This spot was reached only after 
passing five major twists in the cave and was in apparently total dark- 
ness. It was the final outpost of the guacharo nests. Here there were 
no other ant species ; in fact, none of the other three found at the first 
site ventured beyond the lighted portion of the cave. The arthropod 
fauna was sparse in species and biomass and consisted wholly of blind, 
white entomobryids, campodeids, isopods, and snails. 
Just past the second site the cave ceiling dipped to within less than 
a meter of the stream surface, and the passage continued tortuously 
for another twenty meters or so. Beyond, the cave opened into a final 
oblong chamber before dipping beneath the stream surface. In this 
terminal room there were no guacharos; only bats had left a sprinkling 
of guano on the floor. A careful search revealed no Erebomyrma 
workers in the terminal chamber. 
The nest at the first site, near the cave entrance, was located and 
excavated. It was enclosed entirely within a large, smooth shale slab 
partly buried in the cave soil and covered with a thin layer cf dense 
clay. The rock was soft, naturally fractured, and could easily be 
broken apart with a steel trowel. Columns of workers were observed 
traveling from the guano piles to two entrance holes twelve centi- 
meters apart on the upper edge of the rock. The holes were each about 
two millimeters in diameter, and each was surrounded by low, incon- 
spicuous piles of excavated clay. The nest, located only a few centi- 
meters below the surface, consisted of several flat, irregular cavities 
between five and ten centimeters wide and several millimeters in 
height. Probably the great majority of workers and all of the other 
adult castes were collected, both alive and preserved in alcohol. The 
sample, censused the following day, had the following composition : 
547 minor workers, 1 soldier, 10 dealate queens, 10 males. Also 
present was a large quantity of brood, in all stages of development, 
including one male pupa. It was estimated that the entire worker 
population, including that part left foraging or missed in the nest, 
was not less than 600 and not greater than 1000. 
Previous to the excavation, the foraging workers were observed 
briefly. Workers were found up to H/2 meters from the nest entrances, 
but the great majority was within a meter’s radius. Most were hunting 
singly or moving in loose files through guacharo guano, just as Urich 
had found them forty years earlier. Workers returning to the nest 
converged in two separate files, which, judging from the precision 
