1965 ] Haskins and Whelden — Rhytidoponera 109 
Rhytidoponera is of the normal Formicid type, and thelytokous 
parthenogenesis, if it occurs at all, does not make a significant contri- 
bution to the production of females. Such a conclusion has been 
strengthened by the observation of nuptial flights and actual mating 
of males with workers in R. metallica. It has been physically proven 
in the finding by R. M. Whelden of sperm in the spermathecas of 
workers in R. metallica , R. inornata, and R. violacea. 
It is clear from the evidence of collections that, at least in R. 
metallica , R. inornata, R. victoriae, R. aspera, R. croesus , and R. 
strigosa, in addition to the members of the R. impressa group, normal 
alate queens are produced under natural conditions. Numerous such 
queens of R. metallica have been matured in the artificial nest. These 
undertook some flight and dealated but neither mated nor made any 
attempt to found new colonies, although conditions were made as 
nearly optimal as possible. They proved uniformly very short-lived. 
This evidence, taken with the fact that perfect females have never 
been reported in a considerable number of species of Rhytidoponera 
including some of the largest and most conspicuous, and the fact that 
no queenworker intermediate has been reported for any species, 
suggest that the queen-form has been entirely dropped out in the 
“queenless” species, and that members of the R. metallica group (and 
possibly some other forms as well) may be in an intermediate stage 
of evolution, the queen persisting as a rare morphological form but 
being virtually without biological significance. This impression is 
strengthened by evidence both that individual workers, in contrast to 
queens, do show strong instincts of colony formation, and evidence 
that groups of as few as seven workers collected in the field can 
quickly expand to full colony size. 
While such observations answer some questions about the general 
biology and social structure of the “queenless” species of Rhytidopo- 
nera, they raise a great many more. Whelden’s finding of sperm in 
worker spermathecae in R. metallica, R. inornata, and R. violacea 
brought out two additional points of interest. First, sperm-containing 
individuals were relatively abundant in typical colonies of all three 
species collected in the field, ranging from 2.3 per cent of total 
workers in R. inornata to 8.0 per cent in R. violacea. Second, in only 
a few cases were worker spermathecae replete with sperm. Usually 
they were but partly filled, and in several instances only a very few 
sperms were present. This raises the question of whether an individual 
worker is fertilized more than once in its lifetime, or whether it is 
normally exclusively male-producing in the latter part of life. 
It is clear, at any rate, that numerous worker-producing workers 
