340 
Psyche 
[Vol. 85 
Fig. 2. A raiding party of Myniio.xenus gordiaf'ini has just arrived at the nest of 
the host species (photograph: Buschinger). 
returned to their own nest, and at 2030 another file of 5 Myrmoxe- 
nus arrived at the Leptothorax nest. By the next morning, the Myr- 
moxenus colony had moved into the former Leptothorax nest. 
The arena was then subdivided again, and a new Leptothorax 
nest was placed in the position of the former Myrmoxenus nest. 
The second raid, in the same arena, was observed two weeks later, 
on 10 July. Scouting began at 0830 and a successful scout returned 
to the Myrmoxenus nest at 0912. However, in this case, a file did not 
form before 0933. At 1009 a total of 14 Myrmoxenus arrived at the 
target nest, entered it at 1012, and a few minutes later they had 
overwhelmed the colony and were in possession of its brood. Eight 
Leptothorax were immediately stung to death. Contrary to the first 
raid, this time the Myrmoxenus soon began to carry pupae and 
large larvae back into their own nest. One returning Myrmoxenus, 
at 1 150, led a further file of 15 conspecifics to the raided nest. At 
1320 the Leptothorax nest was empty except for a few eggs and one 
Leptothorax male. A total of 26 dead Leptothorax workers were 
counted in the arena, indicating that during this raid more fighting 
had occurred than during the first one. 
Discussion 
Our results, despite the low number of raids observed, reveal that 
Myrmoxenus gordiagini is a slave-making ant. The organization of 
