The nests of Lithurgus collaris were found in dead branches of Hibiscus tiliaceus (L.) (Malvaceae). Mean entrance diameter of the nests was 8.5±1.2 mm (n = 9). The mean tube length and diameter were 65.7±39.6 mm (n = 41, range 7–141) and 7.4±0.7 mm (n = 41), respectively. The main entrance was larger than the gallery entrance. Mean number of galleries per nest was 4.6±3.1 (n = 9). A completed nest was always sealed with wood dust, which was not seen in a new nest. The mean pollen lump length was 21±5.5 mm (n = 9). Larval fecal pellets were thread-like and often extended (5–9 mm) from the abdominal tip. The mean length and width of cocoons were 12.7±0.8 mm and 6.5±0.4 mm, respectively (n = 7). Adults appeared to forage pollen in the first half of the day and nectar during the latter half of the day.