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[Vol. 92 
colonies of ants and other social Hymenoptera, and has its precur- 
sors in presocial insects (Wilson, 1971: 279-281). However, the 
oocytes of unmated sp. 12 workers did not appear different morpho- 
logically to those of inseminated individuals, whereas in some ant 
species at least trophic eggs differ in size, consistency, or both, from 
reproductive eggs (Wilson, 1971: 279-281). 
The life pattern of Rhytidoponera species such as sp. 12 and 
violacea, in which the differentiated queens regarded as normal 
among ants are replaced by mated workers, is paralleled in many 
other ants. Wheeler and Chapman (1922) provided the first such 
observation, for the ponerine Diacamma rugosum, Haskins and 
Zahl (1971) showed that another ponerine, Dinoponera grandis is 
very similar, and a further ponerine, Ophthalmopone berthoudi, has 
recently been examined intensively (Peeters, 1982; Peeters and 
Crewe, 1984). Whereas the ponerine workers all resemble each other 
closely, those of another ant with mated workers, the myrmicine 
Harpagoxenus sublaevis, vary in size and thoracic development, 
and only about 4% of them possess a spermatheca: the mated 
workers form a majority of this 4% (Buschinger and Winter 1975, 
1978). True queens also occur in H. sublaevis; whether a female 
larva has the capacity to develop as a queen or as a worker is deter- 
mined genetically (Buschinger 1978). Workers lack spermathecae in 
Harpagoxenus canadensis and in H. americanus (Buschinger and 
Alloway 1977, 1978), preventing the evolutionary replacement of 
true queens by mated workers in these species; in all three species 
unmated workers may also oviposit. A major difference between the 
ponerine mated worker system and that of H. sublaevis is that H. 
sublaevis colonies possess only one mated egg-layer each, whether a 
worker or a true queen, whereas the ponerines can have many such 
individuals per colony. The polymorphism of mated egg-layers in 
Rhytidoponera species such as metallica and confusa, and in Har- 
pagoxenus sublaevis, and the apparent morphological identity of all 
workers, mated or not, in the ponerines, indicates that the mated 
workers are fundamentally different in evolutionary origin and 
present-day caste-determination dynamics to the ergatoid queens of 
genera such as Myrmecia and Dorylus, with ergatoids differing 
morphologically from workers in the direction of true queens and 
representing intergrades. Wilson’s (1971: 138-139) distinction be- 
tween queens (as fully-developed reproductive females with func- 
