Over the past decade, there has been increased interest in domiciliary aspects of the biology of Triatominae (Hemiptera, Reduviidae), many of which are important vectors of Typanosoma cruzi, causative agent of Chagas disease in Latin America. However, although several problems have been resolved and new programmes for triatomine control have been developed (PAHO, 1993; SCHMUNIS etal., ~~~~;SCHOFIELDD SCHOFIELD & DIAS, 1998), there are important areas concerning the ecology of the sylvatic populations that remain to be more thoroughly investigated. One advantage of studying triatomines in their wild ecotopes is that new concepts can be introduced about spatial distribution of triatomine species and epidemiological risk for human populations. Several observations have delineated the importance of palm trees as ecotopes for 12 of the 13 described species of the genus Rhodnius, and investigators have shown that several Rhodnius species are invading houses with increasing frequency from their sylvatic habitats (DUJAFUXN et al, 1991). In order to understand the spatial distribution of triatomines in their wild ecotopes, we compared the presence and the abundance of a population of R. pallescens in 5 species of palm trees. From 1994 to 1996, we sampled a total of 51 palm trees of the subfamilies Arecoideae (Attalea butyracea, Cocos nucifera and Elaeis oleifera) and Coryphoideae (Sabal mauritiiformis and Copernicia tectorum) in San Onofre (Sucre State, Colombia)-an area classified as tropical dry forest (H0~~~1~~~,1947).Eachpalmwascutdownandthe fronds were removed from stem to crown and meticulously examined for triatomines. R. pallescens was the only triatomine species encountered, and its identity was confirmed with reference to previously described characteristics (LENT &WYGODZINSKY, 1979). A total of 573 R. pallescens (83 adults and 490 nymphs) was collected from the 5 species of palms (Table). There is a significant difference in the densities of R. pallescens captured in each palm species (ANOVA: P < 0.05) with significantly higher densities associated with A. butyratea. The Table gives also information about the anatomy of the palm tree species, showing that, for a series of botanical variables, A. butyracea is always differentiated from the other palm species (ANOVA: P < 0.05). It seems to provide specific architectural features preferred by R. pallescens. A. butyracea is grouped within the Attalea complex which integrates 4 closely related genera, Attalea, Max-