1981] 
Holldobler, Moglich, & Maschwitz — Pella 
351 
forage near the L. fuliginosus nest during the night and stay in 
shelters during the day. They overwinter in dormancy inside the L. 
fuliginosus nest. With the end of winter the beetles enter a second 
diurnal activity phase during which mating takes place. After repro- 
duction the beetles die, normally a few weeks before the new beetle 
generation ecloses in June. 
The behavior of the larvae of Pella 
The description of the behavior of the larvae is primarily based on 
observations in the laboratory. In the field and in the laboratory 
nest, the larvae were almost exclusively found near or in the 
“garbage dumps” of the L. fuliginosus nests. We frequently ob- 
served the larvae feeding on dead ants (Fig. IB). During feeding the 
larvae always attempted to stay “out of sight” either by remaining 
entirely beneath the booty and devouring it from below or by 
crawling inside the dead ant’s body. Occasionally 2-4 larvae could 
be observed feeding on the same ant cadaver. But when they became 
too crowded they frequently attacked each other, sometimes result- 
ing in one larvae eating the other (Fig. 1C). 
When ants encountered the larvae they usually attacked them. 
Almost invariably the larvae reacted with a typical defense beha- 
vior. They raised their abdominal tip towards the head of the ants. 
Usually the ant responded by stopping the attack and palpating the 
larva’s tip (Fig. 1A). In most cases this short interruption was 
enough to allow the larvae to escape. We observed hundreds of such 
encounters between ants and Pella larvae; only a few ended fatally 
for the larvae. 
Histological invesigations revealed that the Pella larvae have a 
complex dorsal glandular structure with a reservoir near the 
abdominal tip in the second last segment. In addition we found 
single cell glands positioned dorso-laterally in each segment. Similar 
glandular structures had previously been found in larvae of the 
myrmecophile staphylinids Atemeles and Lomechusa, and circum- 
stantial evidence strongly indicated that in these species the glands 
produce so-called pseudopheromones which release adoption beha- 
vior in the host ants (Holldobler 1967). We have no evidence to 
suggest that these glands have a similar function in Pella. However, 
it is possible that the more complex glandular structure at the 
abdominal tip, produces an appeasement secretion by which the 
aggressiveness of attacking ants can be briefly blunted. 
