1922] 
The Mating of Diacamma 
205 
a nest of D. rugosum subsp. vagans var. indicum and took to 
be queens, but in 1903 he was compelled to admit that what he 
had seen was “only a large male.” The perusal of his description, 
however, shows that he could not have seen even males of 
Diacamma, for they were colored like the worker and sculptured, 
whereas the male of vagans, of which we have numerous speci- 
mens, is smooth and yellow. There can be no doubt that he 
saw males of a very different Ponerine ant, namely Odontoponera 
transversa Smith, and that he must have been mistaken in regard 
to their belonging with the vagans workers among which he 
found them. 
These failures led Emery (1911, p. 64 nota) to conclude that 
“we must suppose that the female Diacamma resembles the 
worker so closely as to be confused with it.” In 1914 the senior 
author studied D. australe at Cairns and Kuranda in Northern 
Queensland and, after alluding to the failure of previous ob- 
servers to find the missing phase, made the following statement 
(1915b, p. 335): “In excavating the nests of australe, therefore, 
I scrutinized the ants very closely in the hope of finding the 
unknown female, but in vain. Though I searched dozens of 
nests, I saw nothing resembling a winged female or even a 
worker with conspicuously enlarged gaster. I found plenty of 
larvae and pupae and in some of the nests during late October a 
number of males. These are bright reddish yellow, with con- 
spicuously long antennae and quite unlike the bronzy black 
workers. As I failed to find any differentiated queen and as all 
the pupae were of the same size, I feel confident that in Diacamma 
the egg-laying function must be usurped by one or more fertile 
workers during the breeding season.” 
That the assumptions of Emery and the senior author were 
well founded has now been demonstrated by the junior author’s 
observations on D. rugosum subsp. geometricum Smith in the 
Phillippines. During a sojourn of six years at Dumaguete in 
Negros Oriental he found D. geometricum to be a common ant 
from sea-level to about 3000 ft., living in open “cogon” or 
shrubby places along the edges of forests, where the vegetation is 
only three or four meters high. Here it nests under the bark of 
