1981] 
Ward — Rhytidoponera impressa. II 
115 
Table 4. Composition of 322 confusa colonies, with respect to numbers of cocoons 
and alates, and month of collection. Large standard deviations are due to variation in 
colony size, and to the fact that not all nests produce alates in a given season. 
Month 
Sample Size 
<#colonies) 
# worker cocoons 
mean ± S.D. 
# alate cocoons 
mean ± S.D. 
# alates 
mean ± S.D. 
Sept. 
13 
0.0± 0.0 
0.0+ 0.0 
10.8+13.9 
Oct. 
47 
0.2± 0.5 
0.0+ 0.0 
5.3+12.7 
Nov. 
42 
3.6+ 6.5 
0.0+ 0.0 
0.2+ 1.5 
Dec. 
13 
16.3+27.7 
5.7+14.6 
0.1+ 0.3 
Jan. 
24 
43.0+55.3 
16.9+38.0 
0.0+ 0.0 
Feb. 
10 
62.8+40.1 
15.9+15.7 
1.0+ 2.8 
Mar. 
15 
20.5+25.2 
3.9+ 5.2 
6.9+ 8.3 
Apr. 
26 
27.5+32.5 
1.8+ 4.4 
23.1+29.9 
May 
41 
0.4+ 1.2 
0.0+ 0.0 
12.7+21.4 
June 
50 
0.1+ 0.3 
0.0+ 0.0 
25.5+39.0 
July 
32 
0.0+ 0.0 
0.0+ 0.0 
25.0+29.7 
Aug. 
9 
0.0+ 0.0 
0.0+ 0.0 
21.9+34.1 
summer, and that development proceeds rather slowly. Of the 17 
dealate females collected with eggs or no brood at all, 13 came from 
spring and early summer months (October-December) and only 4 
from the fall (April-May) (Table 3). These findings are consistent 
with the observation that virgin alates usually remain in the nests 
throughout the winter, and fly in the spring. Nevertheless the 
occurrence of a few incipient colonies in apparently early stages of 
development in April and May requires some explanation: it seems 
likely that either development was hindered in these colonies or that 
occasional fall mating flights occur. 
Colony foundation in the spring and early summer appears to be 
the pattern followed \n purpurea: Brown (1954) noted many colony- 
founding dealate females of this species in October and November 
on the Atherton Tableland, north Queensland. 
Forty-one of the 43 incipient colonies listed in Table 3 contained 
only a single queen. The two instances of primary pleometrosis 
(colony foundation by more than one queen) both involved colonies 
in a very early stage of development, without brood. One of these 
pairs (acc. no. 1996) was brought into the lab, and colony 
development was monitored. The two queens cohabited peacefully 
from 3 October, 1976 until the end of December, at which time the 
colony contained 12 eggs, 8 larvae and 8 worker cocoons. The first 
worker emerged 2 January, 1977; four days later (after a second 
