1929 ] Further Notes on the Habits of Harpagopenus americanus 49 
tion it behaved in a most apathetic manner and was quickly 
dispatched by the Leptothorax workers before it showed any 
signs of pugnacity. Since the wings are very easily removed 
it does not seem probable that this initial quiescence can be 
due to the shock of the operation. A more likely explanation 
appears to be that the high degree of excitability so charac- 
teristic of the actions of many of the queens of the social 
parasites is in some way connected with the degeneration of 
the wing muscles. Such a process would require an appre- 
ciable lapse of time before it could become effective. 
The results of nine experiments in which an artificially 
dealated Harpagoxenus female was introduced into a nest of 
Leptothorax longispinosusis may be summed up as follows : 
The strange queen almost immediately approaches the 
brood and is at once attacked by the Leptothorax workers. 
She defends herself with extreme ferocity, biting off the 
antennae and legs of her assailants with quick, jerky move- 
ments and giving them little opportunity to seize her. When- 
ever possible the Harpagoxenus queen returns to the brood 
and drives away the Leptothorax workers who are moving 
the larvae and pupae. Her bursts of savageness are some- 
times interspersed with periods of apathy during which she 
remains completely inactive and allows the Leptothorax work- 
ers to drag her about the nest. Eventually she maims or 
kills all the Leptothorax workers and takes possession of the 
brood. The Leptothorax queen is seldom attacked, since she 
avoids the intruder, but usually dies at the end of a few 
days, apparently from starvation. It is interesting to note 
that the Leptothorax callows very rarely show animosity or 
fear for the Harpagoxenus queen and are never molested by it. 
In addition to the experiments with dealated females a 
few observations were made on Harpagoxenus brood. One 
mixed nest which was taken on June 15 contained a large 
number of larvae, most of which subsequently proved to be 
Harpagoxenus. The length of the larval period could not be 
determined but the pupal period of the males and females is 
from twenty-three to twenty-five days. That of the worker 
is a day or two longer. There is no callow period for either 
worker or sexual forms. All are deeply colored at the time 
of emergence. 
