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Psyche 
[Vol. 93 
to the other and the move was obviously caused by a nearby 
community of stack ants ( Formica rufa) which disturbed the ants 
at their previous location. During a period of 20 minutes, 8 
Tomognathus workers were seen being carried in the usual 
manner by the Leptothorax workers. In addition, one Tomo- 
gnathus worker was seen walking at the heels of a Leptothorax 
worker toward the new nest. The former held its head and anten- 
nae on the abdomen of the Leptothorax worker and seemed to 
get very agitated if it lost its guide during an unexpected turn and 
did not find it immediately. As is usual during this kind of guid- 
ance, the following ant carefully duplicated every little turn made 
by the guide.” 
The last few lines of this passage are a fairly accurate description of a 
tandem run; and the last line indicates that Adlerz was quite familiar 
with this recruitment technique. 
Recent studies of the nest emigration behaviour of various Har- 
pagoxenus species by Stuart and Alloway (1985) tend to confirm 
Adlerz’s observations. Slaves in these mixed colonies are generally 
responsible for the bulk of the moving effort during nest emigra- 
tions: they transport brood and their adult nestmates, and lead 
tandem runs between the two nests. Slave-maker workers some- 
times follow in slave-led tandem runs, and H. americanus and H. 
canadensis followers are relatively common. However, Stuart and 
Alloway did not observe any H. sublaevis followers in their study. 
Nonetheless, H. sublaevis followers have been observed in slave-led 
tandem runs to food (Buschinger and Winter 1977), and they prob- 
ably occur occasionally during nest emigrations as well. 
Various species of nonparasitic leptothoracine ants use tandem 
runs for recruiting nestmates to food (Moglich et al. 1974), during 
nest emigrations (Moglich 1978), and for recruitment into battle 
(Stuart and Alloway 1983); and certain leptothoracine slave makers, 
including H. sublaevis and H. canadensis, lead tandem runs during 
their slave raids (Buschinger et al. 1980, Stuart and Alloway 1983). 
Other slave makers in this group, including H. americanus, le&d 
processions during their raids (Wesson 1939, Alloway 1979, 
Buschinger et al. 1980) and these processions constitute one of the 
more advanced recruitment techniques thought to be evolutionarily 
derived from tandem running (Wilson 1971, Stuart and Alloway 
