1982] 
Holldobler — Cerapachys 
5 
again and moved in direction toward the Pheidole nest tube. It was 
closely followed by 17 nestmates. The leading scout ant continued to 
move with its abdominal tip close to the ground, but intermittently 
it paused or moved much slower while raising its gaster slightly 
upwards (Fig. 1). When the Cerapachys column arrived at the Phei- 
dole nest tube they invaded it and attacked the Pheidole workers 
and soldiers. Pheidole fought back but without any effect. The heav- 
ily sclerotized and specially protected Cerapachys (Fig. 2) were not 
at all affected by the mandibular grip of the Pheidole soldiers, even 
when they were attacked simultaneously by 3-5 Pheidole (Fig. 3). 
Although Pheidole outnumbered the Cerapachys invaders more 
than 10 times, they were rapidly disabled by the obviously very 
Figure 1. Recruiting Cerapachys worker, (a) Worker walking with its abdomi- 
nal tip close to the ground, (b) Worker raising the gaster upwards; arrow indicates 
the position of the opening of the pygidial gland. 
