66 
Psyche 
[Vol. 89 
sexuals, and brood were found at all levels of the nest and were 
quickly aspirated. 
Distribution and natural history 
A. pallipes has been found in the eastern United States and in the 
St. Lawrence Valley in Canada in cool, moist, forested areas 
(Brown, 1960). General references on the natural history of this 
species are given by Wheeler (1900) and Haskins (1928). 
Laboratory arrangements 
Colonies were housed in artificial nests composed of a thick, 
moist filter paper bottom with cotton sides approximately 6 mm 
high covered with a glass plate. The nests were placed in 15 X 22cm 
plastic boxes in which the humidity was kept high. The total nest 
area was roughly 10cm 2 . A second chamber, similar in structure but 
somewhat larger, was connected to the nest as a foraging arena, 
where live prey were offered. Colonies were fed on whole, live geo- 
philomorph and lithobiid centipedes; in addition, elatyrid, bupres- 
tid, and tenebrionid beetle larvae were acceptable to the ants. This 
method of culture proved successful and greatly facilitated studies 
of social interaction since the activity of an entire colony could be 
monitored on the stage of a dissecting microscope. Ethogram data 
were compiled in this manner, and were analyzed using the methods 
of Fagen and Goldman (1977). 
Results and Discussion 
1. Life cycle and population structure. 
Nest distribution and colony size. The spatial distribution of col- 
onies at the principal study site in Westford is presented in Fig. 1. 
An interesting feature of this population, in addition to its clumped 
distribution pattern is that three colonies were collected under 
stones in 1978 precisely where colonies were found the year before. 
This suggests that the colonies that were collected represented sub- 
units of a large, subterranean population. Each unit is small (modal 
size class = 9-16 workers). Complete collection data are presented in 
Fig. 2. Although distributional data are not given, a population of 
seemingly comparable density was discovered by Wheeler (1900), 
who uncovered 30 nests in a three hour period. Also, the colony size 
data correspond closely to the data of Francoeur (1965, 1979, and 
personal communication). 
