Members of the genus Monomorium can be distinguished by the following characters:
monomorphic to polymorphic; antennae 10–12 segmented (most frequently
12), usually with a conspicuous 3-segmented club; mandibles with 3–5 teeth, median
clypeal seta conspicuous; median portion of clypeus raised, the raised section
longitudinally bicarinate; the carinae usually distinct; metanotal groove present,
commonly impressed; propodeal dorsum usually unarmed and rounding into the
declivity; propodeal spiracle usually circular, located at about the midlength of the
sclerite (Bolton 1987).