12 
Psyche 
[February 
Fig. 1. A, worker of Harpagoxenus americanus; B, worker of Leptothorax cnrvispinosus , 
after Wheeler. 
During the past summer I found a number of nests of H. 
americanus near Tuxedo, N. Y., and was fortunate enough to see 
these ants engaged in slave raids. In all but one nest the slave 
ant was L. longispinosus. The remaining colony contained 
slaves of both L. longispinosus and L. curvispinosus, a condition 
parallel to that described for the European H. sublcevis, which 
enslaves both L. acervorum and muscorum. Dr. Wheeler pos- 
tulated that such colonies should occur, since he found a queen- 
less longispinosus-curvispinosus colony in the vicinity of the 
Harpagoxenus nests. However, since he did not think H. 
americanus a dulotic ant, he considered the colony as one which 
needed only the advent of a dealated Harpagoxenus queen to 
form a mixed colony containing two species of slaves. For 
reasons to be subsequently given I would consider Dr. Wheeler's 
mixed Leptothorax colony as a remnant, originally formed by 
dulosis, from which the Harpagoxenus had migrated or been killed 
off while raiding. 
Before taking up the discussion of H. americanus it seems 
advisable to briefly outline the ethology of the European species. 
H. sublcevis has been known since 1848, and since that time a 
number of observations have been made on its habits. It appears 
to have a wider distribution than its American cogener, for it has 
