4 
Psyche 
[Vol. 89 
Collection, ANIC, Canberra) were collected from nests in the soil in 
a sclerophyl scrub pasture near Eungella, North Queensland (Aus- 
tralia). One colony had a single ergatoid queen; the other colonies 
had two ergatoid queens apiece. Each colony was housed in separate 
glass tube nests (8cm X 0.6cm c />), with water trapped at the bottoms 
behind cotton plugs. Each nest tube was placed into arenas of 
varying sizes, depending on the experimental design. Histological 
studies were conducted according to the procedures described in 
Holldobler and Engel 1978. Additional methodological details will 
be given with the description of the individual experiment, as pre- 
sented below. 
Results 
Raiding behavior and paralysis of prey larvae 
Species of the genus Cerapachvs seem to preferably prey on ant 
species of the myrmicine genus Pheidole (Wilson 1958; Brown 
1975). When 1 provided Cerapachvs with colonies or fragments of 
colonies of a variety of species of the genera Iridomyrmex, Meranop- 
lus, Monomorium, Crematogaster, Pheidole, Stigmacros, Polvrha- 
chis, Camponotus (placed in a 65 X 120cm arena) they preyed freely 
only on Pheidole. They also accepted Monomorium larvae as prey, 
but only when these insects were directly inserted into the Cera- 
pachys nest. When the Cerapachvs workers encountered workers of 
the other species, or came close to their nest tubes, they usually 
showed avoidance behavior. The reaction was very different, how- 
ever, when individual scouts of Cerapachvs discovered the nest tube 
of Pheidole (accession #209, voucher specimens in ANIC). The Cera- 
pachys worker vigorously vibrated its short antennae and moved 
slowly into the nest tube, which contained approximately 200 Phei- 
dole workers and soldiers and about 150 larvae and pupae. It did 
not venture very far into the foreign nest but left after a short while 
and ran, in a somewhat meandering route, back to its own nest, 
located 70cm away from the Pheidole nest. During honyng it 
appeared frequently to touch the ground with its abdominal tip, as if 
it were laying a chemical trail or depositing scent spots. Seconds 
after it had entered the nest of its own colony, its n^stmates became 
very excited. Many grouped around the scout ant, which repeatedly 
raised its gaster upwards. Within one minute the scout left the nest 
