Agonistic displays of larval Diphlebia euphoeoides, an amphipterygid damselfly, are described. Damselflies are conventionally regarded as consisting of two broad taxonomic divisions, namely ‘narrow-winged’ damselflies and ‘broad-winged’ damselflies. Agonistic displays are known from many larval ‘narrow-winged’ damselflies. This is the first description of agonistic behaviour in the larva of a ‘broad-winged’ damselfly. Twenty six major displays were distinguished. Several new major displays, unlike those described for any other odonate larva, were found. Other display motor patterns showed a strong similarity with those recognized in larval Coenagrionidae. Such displays probably represent symplesiomorphies. The potential use of larval agonistic display characters in phylogenetic analysis is discussed. Contrary to recent hypotheses on turnover of agonistic displays, change within odonate lineages appears to be very slow.