1975] 
Jeanne — Stelopolybia 
263 
one occasion I observed wasps landing on and dragging their gasters 
over objects as far apart as 10 meters along a line perpendicular to 
the direction of swarm movement. 
On two occasions an attempt was made to determine when queens 
moved by netting samples of wasps as they passed a point along the 
route. Beginning at 1735 on 5 February the numbers of workers 
(queens in parentheses) netted in successive three-minute intervals 
were: 10 (o), 9 (o), 8 (o), 3 (2), 4 (2), 5 (o), 1 (1), 2 (1), 
6 (1), 4 (o). On 6 February beginning at 1615 the results were 
o (o), 1 (0), 2 (o), 2 (o), 1 (1), 5 (1), 7 (o), 3 (o), 1 (o). 
The scanty results reflect the difficulty of netting wasps due to the 
diffuse nature of the moving swarm. Though sample sizes are small, 
the results suggest that queens do not begin moving to the new 
site until 10 or 15 minutes after the first workers begin to move. 
The swarm could be followed only by moving from one dragging 
site to the next. It was possible to first roughly localize the new 
swarm site by noticing the point beyond which no wasps were 
observed dragging. Pinpointing the site was sometimes difficult, be- 
cause of the rather wide path that was followed by the wasps. This 
was especially true in dense vegetation, where there were many 
possible sites available. It was usually possible to find the swarm 
by searching for unusually dense aggregations of flying wasps. Upon 
arrival of the bulk of the population at the new site the swarm 
usually settled down fairly quickly. This behavior made it much 
easier to locate the swarm in the new site while wasps were still 
arriving, rather than later. On some occasions arriving wasps 
seemed to overshoot their goal and could be seen searching beyond 
the new site. In one case several wasps were seen hovering about 
the tip of a de'ad tree some 1 1 meters beyond the newly settled 
swarm. 
Discussion 
The behavior described herein is very similar to what Naumann 
has observed in Polybia catillifex, P. oecodoma , Stelopolybia myrme- 
cophila, Leipomeles dorsata, and Angiopolybia pallens (Naumann, 
1975). As Naumann concluded, it strongly suggests involvement of 
a trail pheromone. The dragging behavior could well function to 
deposit scent marks on prominent objects along the swarm route. 
Following swarm members may then pick up the scent by hovering 
downwind of such marks or by landing on marked objects and 
inspecting them with their antennae. 
