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Psyche 
[Vol. 95 
It was therefore of particular interest when Iridomyrmex humilis 
was noted in Bermuda in 1953, the original focus having been 
reported at Waterville in Paget, where it was probably introduced 
with nursery stock. By late 1953 seven new foci had been identified, 
and the invader was well on its way to challenging P. megacephala 
for “possession” of the Island (Crowell, 1968). In 1955 the Bermuda 
Department of Agriculture officially recognized /. humilis as a 
“major economic pest”, and roadside surveys were conducted by the 
Department, under the direction of I. W. Hughes, tracing its expan- 
sion from 1955 to 1959. 
In 1959, and twice in 1963, Haskins and Haskins (1965) con- 
ducted “point surveys” which indicated that by that time Iridomyr- 
mex had occupied a large part of the Island and was actively 
replacing megacephala in many districts widely dispersed through- 
out Bermuda. At that time these authors raised the question of 
whether the ultimate outcome of this competition would be com- 
plete elimination of one of the species (probably P. megacephala ), as 
occurred in Madeira, or whether a long term “permanent” but shift- 
ing equilibrium would result. 
The 1959/ 1963 survey was followed in 1966 by a more complete 
one by Crowell (1967), undertaken in the same basic mode as the 
previous ones, and including a summary of earlier surveys. Finally, 
the most complete survey to date was accomplished by Lieberberg, 
Kranz, and Seip (1975) in 1973, again using methods basically sim- 
ilar to those of the preceding censuses. Thus a fairly complete pic- 
ture was achieved of the interactions of humilis and megacephala 
over nearly two decades. So far as we are aware, no detailed surveys 
were made, so it seemed that a final one should be undertaken, 
thirty-three years after the first official report of the arrival of I. 
humilis. That effort is the subject of the present note. 
Methods and Results 
In some respects this last survey was disappointing. So much land 
in Bermuda has been committed to building and to “artificial with- 
drawal” in other developments eliminating or greatly modifying 
many of the sites included in the earlier surveys, and the density of 
motor traffic has so much increased that any repetition of the sur- 
veys in the older “roadside observation” mode was not only deemed 
impracticable, but would have been unrepresentative, in our view. 
