Abstract and Summary
Parischnogaster nigricans serrei (Du Buysson) forages almost exclusively on little arthropods that females, in flight, pick off of spider webs. The foundress performs such extranidal activities as foraging, pulp and water collection only in the pre-emergence period, after which she leaves the nest only for defensive flights and to defecate. Males hover near forest landmarks that they defend against other males in ritualized aerial fights. The daily patrolling periods of male P. nigricans and P. mellyi (the only two species living in the observation area) do not overlap and occur in the central hours of the day. It is quite probable that this behaviour is related to reproduction.