PSYCHE 
VOL. XXXIV. FEBRUARY 1927 
No. 1 
THE SOCIAL PARASITISM OF THE ANT 
HARPAGOXEN US AMERICANUS 
By A. H. Sturtevant 
Columbia University, New York City. 
Harpagoxenus americanus was described by Emery (1895), 
from workers found by Pergande in a nest of Leptothorax cur- 
vispinosus Mayr at Washington, D. C., and from a single specimen 
collected by Schmitt at Beatty, Pa. Schmitt later informed 
Wheeler (1910) that this and a few other specimens were taken 
while he was sifting for beetles. There was no evidence as to 
their habits or any association with other ants. Wheeler (1905) 
found three nests at Bronxville, N. Y., that contained H. amer- 
icanus and L. curvispinosus. One nest contained a single Har- 
pagoxenus worker, another six, and the third eight workers and 
a dealated queen. In 1925 I found a nest (Sturtevant 1925) at 
Tarpaulin Cove, Naushon Island, Mass., that contained both 
H. americanus and L. curvispinosus. So far as I have been able 
to discover, these are the only recorded occasions on which H. 
americanus has been collected. 
During the summer of 1926 I was fortunate in finding 16 
nests of the species, at three different localities in New Jersey. 
Included in the new material are three kinds of individuals not 
previously described: males, winged queens, and individuals 
that look like workers but have rudimentary ocelli. I have also 
been able to make a few observations on the habits of the species. 
The present paper contains an account of this new material, 
with a discussion of the previous data and a comparison with the 
European species, H. sublcevis, studied by Adlerz (1896) and 
Yiehmeyer (1908, 1921). 
