1981] 
Ward — Rhytidoponera impressa. II 
117 
MAR APR MAY JUN JUL AUG SEP OCT NOV DEC JAN 
( 7 ) ( 19 ) ( 20 ) ( 24 ) ( 27 ) ( 6 ) ( 13 ) ( 39 ) ( 20 ) ( 4 ) ( 4 ) 
Figure 2. Maximum larval length per nest (measured in millimeters, with larva in 
natural resting position), in relation to time of year, for 1 83 nests of confusa. One larva 
(the largest) was measured in each nest. Figures in parentheses indicate the number of 
nests sampled. No data available for February. 
dominantly male only. Figure 1 summarizes the seasonal changes 
for confusa and cha/ybaea, in terms of the proportion of colonies 
containing various stages of brood or alates, for each month. Data 
on absolute numbers of worker cocoons, alate cocoons, and alates 
are given in Table 4 for 322 confusa colonies (similar patterns are 
shown by chalybaea, but numbers average higher). 
In confusa and chalybaea there appear to be two peaks of egg 
production — one in the spring (September-October) and another in 
the late fall (February- April). Larvae are continually present; those 
overwintering are small to medium-sized and show little growth 
until the spring, when development proceeds rapidly (Figure 2). 
Worker cocoons first appear in October-November, and not until 
