1981 ] 
Ward — Rhytidoponera impressa. II 
125 
worker-reproductive colonies in which one or more mated “work- 
ers” occur in lieu of a queen. It appears that worker-reproductive 
colonies normally reproduce by colony fission or budding, although 
information on this process is fragmentary. Queenright colonies are 
founded by lone queens. Colony-founding queens are most fre- 
quently encountered in the spring and early summer; such queens 
leave the brood chamber to forage for food. 
In mature colonies of confusa and chalybaea, the development of 
brood and production of alates is highly seasonal (and essentially 
similar for both queenright and worker-reproductive colonies). One 
crop of workers and alates is produced each year, the former 
eclosing from cocoons between January and June, the latter 
between February and April. Most or all alates overwinter in the 
nest (along with small to medium-sized larvae), and are released in 
the spring (September-November). Similar seasonal patterns are 
shown by impressa, purpurea (in Australia), and enigmatica, except 
that colonies of enigmatica generally do not retain alates over the 
winter. 
In the population of chalybaea on the University of Sydney 
campus, mating flights took place in early October for 3 consecutive 
years. During these flights, flying males became concentrated into 
clusters around nest entrances where they attempted to mate with 
workers, with males, and with the occasional alate female. Several 
worker-male but no queen-male matings were observed in these 
nest-associated swarms. Like males, queens appear to disperse some 
distance before mating, and possibly utilize mating sites other than 
nest entrances. 
Acknowledgements 
This work was supported by an Australian Commonwealth 
Scholarship. Additional support from L. C. Birch and the Univers- 
ity of Sydney is gratefully acknowledged. 1 thank D. Feener and A. 
Forsyth for comments on the manuscript. 
References 
Brown, W. L. 
1953. Characters and synonymies among the genera of ants. Part I. Breviora, 
11 , 1 13 . 
