1950] 
Haskins and Haskins 
Brachyponera lutea 
5 
ishment supplied by its own body and had itself survived for 
ninety days without food. This represented a much closer ap- 
proach to the claustral condition than could be achieved among 
the lower Ponerinae, and it was clear that the question of the 
intermediate evolutionary stages in colony formation exhibited 
among the higher Ponerinae merited further investigation. 
Perhaps the most interesting of all Ponerine ants for studies 
of this kind is the Australian species Brachyponera lutea , be- 
cause of the great disparit}^ of size and differentiation of bodily 
structure between the perfect females and workers, in which it 
is unique among the Ponerines but approaches rather closely 
the condition among higher ants. It might be expected that in 
this species, above others, a close approach to the claustral 
mode of colony foundation might be achieved. Accordingly, 
observations were undertaken in the field and in the artificial 
nest which are recorded herewith. 
Brachyponera lutea 
The genus Brachyponera was considered by Emery ( Genera 
Insectorum ) as a subgenus of Euponera, and exhibits close 
affinities with that group, and with the genus Ponera s. str. in 
many respects of structure and behavior. As in Euponera, it is 
composed of active ants of wide distribution, showing a remark- 
able degree of variability and of plasticity of habit for a 
Ponerine group. In the majority of forms of Brachyponera, as 
in Euponera , the stature of the perfect females and of the 
workers is rather similar. In two species, however, B. sennaaren- 
sis Mayr of tropical Africa and B. lutea Mayr of Australia, the 
workers are very much smaller than either sexual form. In 
B. lutea this differentiation reaches an extreme both qualita- 
tively and quantitatively, the workers averaging but 4—5 mm. 
in length and being of a pale yellow to brownish coloration, 
while the queens attain dimensions of 10—11.5 mm., are of 
brownish black pigmentation, and carry so much fat-bodv that, 
their form is very different from that of the workers as, indeed, 
from the typical form of Ponera or Euponera. 
The species was first described by Mayr (1868, 1876). The 
extraordinary difference in stature and appearance between 
queens and workers caused Crawley (1918) to call the co- 
specificity of the described types into question. The cospecificity 
