288 
Psyche 
[September-December 
ants readily attempted to bite the larvae but were unable to grasp 
a larva firmly with their mandibles from a dorsal approach because 
the dorsal surface was too convex. If however an ant came into 
contact with the head or ventral region there was a very rapid strike 
response from the larva. The larva struck at the ant with its 
mandibles as it coiled more tightly into the C-shape. A dark fluid 
was released from between the larval mandibles at the time of the 
strike. As the larva wriggled to escape, several wet fecal pellets 
were expelled which had a deterrent effect on aggressive ants. There 
was also a strong, unpleasant odor associated with the mandibular 
and anal secretions. 
The above reaction was repeated until the mandibles made con- 
tact with and crushed the body of the ant. When this happened 
the ant immediately released its grasp of the larva and within a few 
seconds it collapsed. Movement was usually limited to tremors of 
the appendages until death occurred. Occasionally a beetle larva 
was fatally injured by attack from too many ants. The mandibular 
strike was most effective when a minor worker ant was attacked by 
a third instar larva. 
Adult Defense 
When first attacked, the beetle assumed a characteristic death 
feigning posture with all its legs out and slightly up at the sides. 
In the laboratory this position was seldom held for less than 5 
minutes and showed little habituation. The ants grasped the beetles 
by their legs and pronotal projections and dragged them randomly 
about, eventually releasing their hold. Host ants regularly attacked 
beetles on the mound surface but as the beetles burrowed down 
into the thatch, most of the ants were removed. Beetles were 
able to penetrate the mound surface in less than one minute. In 
addition the beetle’s heavily sclerotized integument, retractible an- 
tennae, and concealed mouth parts also represent adaptations for 
survival in ant nests. 
If the beetle was violently disturbed or turned over by the ants, 
a droplet of viscous fluid was released from the anal opening. 
This fluid had an offensive odor and was effective in repelling the 
ants. When an ant came into physical contact with this fluid, it 
became agitated and spent considerable time grooming. Defensive 
secretions have been documented for other myrmecophiles (Holl- 
dobler, 1970; Blum et. al., 1971) and their discovery in other species 
of Cremastocheilus is expected. 
