The pholcid spider Mesabolivar aurantiacus (Mello-Leitão 1930) is common in forests of Trinidad, West Indies. Its webs are often found to contain the nabid bug Arachnocoris trinitatis (Bergroth 1916). In a lowland forest in August-September 2003 (wet season) we censused 81 M. aurantiacus webs for occupancy by the spider and the insect. A. trinitatis showed no significant preference for webs occupied by either juvenile or adult spiders. However, it showed a preference for empty webs, suggesting that it utilizes these as a ready-made preycapture device, and possibly as a site for finding mates.