Megalomyrmex wallacei Mann

(Fig. 2 A)

Megalomyrmex wallacei Mann, 1916: 445, pl. 3, fig. 28. Lectotype queen (designated by Brandão 1990: 426): Porto Velho, Rondonia, Brazil [MCZ] (not examined). Paralectotype worker: same data [MZSP] (not examined). Brandão, 2003: 150, description of male. See also: Brandão, 1990: 426.

Measurements. Worker: HW 0.98–1.03, HL 1.13–1.18, SL 1.50–1.58, ML 1.78–1.85 (n=30, from Brandão, 1990).

Geographic range. Brazil (Amazonas, Rondonia, Pará, Tocantins), Guyana, Colombia, Costa Rica (Brandão 1990, 2003).

Biology. This species occurs in mature wet forest, usually low-elevation rainforest. Brandão (2003) reports the species nesting under leaves on the forest floor, in colonies of up to 300 workers. In Costa Rica, workers have been collected at baits on the forest floor, and one nest was observed at La Selva Biological Station. It was inside a 6cm long rotten cacao pod on the trunk of a cacao tree. The nest contained 93 workers. There was no morphologically distinct queen, but there was abundant brood of all sizes, from eggs to pupae. The workers showed considerable size variation, and larger workers had an enlarged mesonotum.

Material examined. COSTA RICA: Heredia: La Selva Biological Station, 10°26'N, 084°01'W, 50 m, 29 Jul 1995 (J. Longino); Puntarenas: Los Planes, Corcovado National Park, 08°38'N, 083°40'W, 100 m, 4 Dec 1981 (J. Longino); GUYANA: Rupununi: Karanambo, 03°45'N, 059°20'W, 100 m, 16 Jan 1981 (J. Longino).