io6 
Psyche 
[March 
lica, if fertilized, may be capable of founding new colonies. It seems 
somewhat more likely, however, that under natural conditions new 
colonies are normally formed by the detachment from the parent nest 
of worker groups which include one or more fertilized individuals. 
Even though initially very small, such parties may expand rapidly in 
numbers and reach the status of full-fledged colonies in a remarkably 
short time. Thus on December 21, 1963, two isolated groups of 
workers were taken at Sutherland, N. S. W. One consisted of 7 
workers, about 6 cocoons, and a few young larvae; the second, also of 
7 workers, with 2 cocoons and about 6 young larvae. These two 
groups were colonized in the usual fashion in modified earth-contain- 
ing nests, and housed throughout their history in adjacent arenas on 
the same laboratory table. On January 17, 1965, the first group 
included the following: 
74 living adult workers. 
127 dead workers found on the kitchen middens. 
* 4 dead males found on the kitchen middens. 
55 cocoons, which were opened and examined, and found to contain: 
26 worker pupae. 
9 semipupae, believed to be of workers from the size and shape 
of the cocoon. 
* 11 male pupae. 
7 semipupae, believed to be of males from the size and shape of 
the cocoon. 
2 fresh-spun cocoons with larva present. 
54 larvae of various sizes. 
Several groups of eggs, totaling about 100. 
Thus at least 227 workers and 15 males had matured to the pupal 
stage and beyond. In sharp contrast, the second group at the same 
date was found to contain 5 adult workers (almost certainly of the 
original 7 ) , 2 males, and 3 cocoons, 2 of which contained male pupae 
and the third a semipupa. Thus this group as collected apparently 
had not included a fertilized worker. 
It is particularly interesting, in view of the normally nonseasonal 
production of males in R. metallica , that at least 15 males were ma- 
tured within the first year of life of this colony. This situation may 
be contrasted with the case of a colony of Ectatomma ruidum* ** kept 
under observation, from its establishment by the original female, over 
a ten-year period in the artificial nest. Here no males whatever 
appeared until near the close of the fourth year of community life. 
*Note presence of males at this early stage in colony development. 
**An abundant New World Ectatomiine species with a well-defined alate 
female caste, forming communities which are commonly if not always 
monogynic. 
