1981] 
Ward — Rhytidoponera impressa. II 
121 
Figure 3. Section of University of Sydney campus where chalybaea nuptial flights 
were observed. A, B, and C represent sites of large clusters of alates, described in text. 
Lesser numbers of alates were observed at locations U3, and elsewhere. 
seconds, after which separation occurred. Wings were vibrated 
rapidly during attempts by males to mount workers. A mating 
attempt by one male often attracted others, resulting in a buzzing, 
frolicking ball of males. Males were also observed to enter (and 
leave) the nest, and may perhaps have mated with workers within 
the nest. Several instances were noted of workers forcibly evicting 
males from the nest, dragging them to a distance of 1 meter from the 
nest entrance. Workers were still foraging during these events: two 
which were observed returning with a dead honey-bee, and another 
with a seed, were unmolested by males. 
Sites B and C. Similar observations were made at these sites 
(Figure 3), with large numbers (> 100) of alates and workers 
clustered in the vicinity of nest entrances, along sandstone walls. A 
few alate females were also seen among these swarms. Despite 
persistent attempts by males, no successful worker-male or queen- 
male matings were recorded. There was a noticeable decline in 
swarming activity by early afternoon. 
Male alates were observed in smaller numbers at several other 
places on campus, particularly at Sites 1, 2, and 3 (Figure 3). A 
single, inseminated dealate female was encountered at Site 3 in mid- 
afternoon, apparently searching for a nest site. During the day, 
samples of alates were collected from each observation site. Out of a 
total of 293 alates, 279 (95.2%) were males, and 14 (4.8%) were 
females. 
