XII. Further Observations on Temporary Social Parasitism 
and Slavery in Ants. By Horace Sr. J. K. Donts- 
THORPE, F.Z.S. 
[Read December 7th, 1910, ] 
TuHIs year I have been able to make a few more observa- 
tions and experiments on Temporary Social Parasitism and 
Slavery in Ants, both in nature and in my observation 
nests. In my two previous papers (Nos. 39 and 42) I have 
explained show the queens of ants of the Formica rufa 
group found their colonies in a nest of Formica fusca and 
its races. It may, however, be as well to briefly recapitu- 
late these facts when dealing with the different species 
referred to in this paper, giving at the same time my new 
notes and observations. I do not deal here with colonies 
founded by branch nests, or by queens accepted back into 
their own, or other nests of the same species, but only 
when a queen, after her marriage flight, has entered a 
nest of another species. 
Formica rufa, L.—Wher a queen of this species has 
found a new, or weak, or perhaps a queenless nest of 
F. fusca, she enters it after some fighting with the workers 
and is eventually accepted by them. When her eggs are 
laid, the brood is brought up with the help of the fusca 
workers, the 7wfa queen thus becoming a temporary social 
parasite, as when the /wsca workers die off a pure rufa 
nest will remain. It is probable that the rufa queen kills 
the fusca queen if present. On May 15th I visited Park- 
hurst Forest, I. of W., in company with Mr. Taylor of 
Sandown. We noticed several rufa 2 2 at large, some with 
wings and others dedlated. (It is probable there had been 
a marriage flight. I have never seen a marriage flight of 
this species, but Wasmann, who has, notes that it occurs 
from the middle of April onwards.) One of the latter we 
observed near the entrance to a fusca nest. That is to 
say, there were several entrances into the ground in a 
sandy corner, from whence fusca $$ kept coming in and 
going out. We watched the rufa ¢ for a long time; she 
made overtures to the 8 8,and endeavoured to enter their 
TRANS. ENT, SOC, LOND. 1911.-—PART I. (MAY) 
