– Species composition of odon. in aggregations were determined in a Restinga habitat at Espfrito Santo, SE Brazil. In a total of 8h 35 min. of sampling, 2 attacks of A. concolor were observed in large groups, mainly composed of Pantala flavescens and Miathyria marcella. P. flavescens responded to these attacks by pursuing A. concolor. The behaviour of P. flavescens in the aggregations under attack suggests that due to a decrease in the chance of predation, the smaller spp. could gain an extra advantage in these groups.