1957] 
Wilson — Pheidole sitarches 
49 
hurried pace until they encountered a pebble or blade of 
grass under which they could conceal themselves. Deala- 
tion thereafter followed, the female drawing her hind legs, 
one at a time, forward against the wings until the latter 
broke off. After dealation, the females continued to run 
over the ground, evidently in search of a permanent nest 
site. One dealate queen was found lodged in a cavity under 
a small rock within the homesite area. 
Discussion. Several principal conclusions can be drawn 
from the above observations : 
(1) It is almost certain that the individuals comprising 
the swarms were drawn from multiple nests. Incoming 
males were seen to approach from many directions. More- 
over, it does not seem possible that all of the males in the 
individual swarms, which were changing in membership 
constantly, could have been supplied by a single nest. 
Pheidole sitarches apparently does not form very large 
colonies; those near the nuptial flight area appeared to 
contain no more than two or three hundred workers and 
could not have supported many more males at maximum 
capacity. It is likely that the swarms were formed origin- 
ally by individuals attracted to the open spots in the home- 
site area, and thereafter the swarms, oriented to these 
spots, served as the principal attractant foci for individuals 
flying in from the outside. Mixed swarms, of course, result 
in genetic outcrossing and increased population variability, 
processes that are generally of positive adaptive value. 
(2) The sitarches flight is of such a highly specific and 
transitory nature as to seemingly insure that other Pheidole 
species occurring in the same area are excluded. Nearly 
all of the females reaching the swarm are quickly fertilized. 
Moreover, each female is fertilized by only one male, thus 
limiting the potential genetic diversity of single colonies. 
(3) The nuptial behavior is also of such a nature as 
to limit greatly the dispersal power of the species. It is 
probably true that in some species of ants the fertilized 
queens continue flying after leaving the nuptial swarm, 
thereby increasing their dispersal potential, especially if 
they fly upward and are caught in upper air currents. 
