Notes on Trap-Nesting Sri Lankan Wasps and Bees (Hymenoptera: Vespidae, Pompilidae, Sphecidae, Colletidae, Megachilidae)

A trap-nesting study was conducted in Kandy, Sri Lanka, during February to June 1997. Wooden pieces ca. 17 cm long with central grooves of either 3 or 5 mm in diameter were placed outside our residence, providing nesting sites for stem- nesting Hymenoptera. A diversity of solitary wasps and bees, including two new species of Anthidiellum, were found nesting in these 'artificial stems.' Evidence of supersedure was noted, and we give the first report of a probable new subgenus of Hylaeus that uses a mixture of resin and sand for cell construction. Notes on nest architecture are provided for the observed trap- nesters belonging to the families Vespidae, Pompilidae, Sphecidae, Colletidae, and Megachilidae.