290 
Psyche 
[Vol. 92 
seen flying from a swarm with his balloon trailing by a silken thread. 
Upon landing on nearby vegetation the balloons were lost and never 
retrieved. These balloons were probably dislodged during a collision 
with another male in the swarm. It is not known whether these two 
males constructed new balloons and returned to a swarm that even- 
ing. Some individuals left a group, joined another more than 1 m 
away, and sometimes returned to their initial swarm, but in general 
males remained at the same station for the entire swarming period. 
Females perched on vegetation near swarms and flew into swarms 
where coupling occurred. Pairs were easily distinguished from the 
more erratic flight of uncoupled males. Mating (coupling) occurred 
during the last 8 min of the activity period (n = 22 pairs, range 1-19 
min.). When couples were captured, males were mounted atop 
Males per Swarm 
Figure 2. Distribution of swarm size as measured by counting the number of 
balloons in 156 Hilara swarms (spring 1982 & 83). Swarms with more than 10 males 
were estimated to the nearest 5 males. Arrow shows mean size of swarms. 
