Observed interactions between the host-ant Anoplolepis custodiens, and the pupa and final instar larva of Thestor basutus basutus is described.  Larvae frequently interrupted two ants exchanging regurgitations, intercepting the flow of food and substituting itself for the recipient ant.  There are strong indications that both organic detritus and ant brood are supplementary food sources.  This, together with preying on Homoptera in the early instars, implies that this insect exploits all the entomophagous opportunities to which it is exposed.  A Thestor larva was sometimes observed to groom a host-ant.  These behavioural observations are briefly discussed.