24 
Psyche 
[February 
to the west of No. 5. It was plainly an incipient colony con- 
taining a normal dealated Harpagoxenus queen, one Harpago- 
xenus worker and thirty-five longispinosus slaves and a large 
brood composed entirely of larvae. The queen was subsequently 
found to lack the last pair of legs, only the stumps of these re- 
maining. 
This mutilated condition was also true of a dealated Harpa- 
goxenus queen which was taken on Aug. 3rd. This insect, which 
was crawling over a stone when discovered, lacked the left 
antenna and one leg on the left side. It seems likely that it had 
been repulsed in an attempt to enter a nest of Leptothorax, since 
there were two fairly large longispinosus colonies about three 
meters from the stone where the Harpagoxenus queen was found. 
A most careful search failed to reveal any mixed colony in that 
vicinity. 
As may be seen from the foregoing descriptions H. americanus 
presents one striking contrast to the European species. Normal 
winged queens are the general rule with americanus instead of 
the ergatoid females which usually take their place in sublcevis. 
The ergatoid form seems to be as rare in the colonies of amer- 
icanus as are the winged queens in those of sublcevis. I have 
never seen an ergatoid female in any of the colonies thus far 
observed. 
While much remains to be done it is now possible to sketch 
the ethology of H. americanus ; a hasty sketch to be sure with 
many missing features hypothetically supplied, but at least a 
beginning. In this picture we see the fertilized Harpagoxenus 
queen entering a Leptothorax nest by force. Having driven 
away or killed the original owners of the brood she appropriates 
this, tends it and is in turn tended by the resulting Leptothorax 
workers, until in time there arises a mixed colony. When the 
colony is well established the dulotic instinct manifests itself in 
the Harpagoxenus workers. These gain entrance to some Lep- 
tothorax nest after a long struggle in which their greater hardiness 
and superior size finally enables them to kill or intimidate the 
Leptothorax workers. If the external conditions are favorable 
the raid is carried to a successful conclusion and the brood of 
the pillaged nest is carried back to the mixed colony. If the 
