mesosoma
mesosoma lacking erect hairs

mesosoma lacking erect hairs
dense pelt of short hairs

mesosoma with dense pelt of short hairs on dorsal surface (Strumigenys)
mesosoma with erect hairs

mesosoma with erect hairs
three distinct convexities

profile of mesosomal dorsum with three distinct convexities (Linepithema)
two distinct convexities

profile of mesosomal dorsum with two distinct convexities (Linepithema)
no metanotal groove

promesonotum evenly convex, not separated from propodeum by metanotal groove
metanotal groove

promesonotum separated from propodeum by metanotal groove
mesosoma smooth and shining

The mesosoma is entirely smooth and shining, with at most a few isolated punctures, but never with the propodeum, mesonotum or pronotum entirely punctate. Used in Antkey to separate Monomorium ebeninum, Monomorium floricola and Monomorium liliuokalanii from other Monomorium.
short thick erect hairs abundant

short thick erect hairs abundant on head and mesosoma (Crematogaster)
short thick erect hairs sparse

short thick erect hairs sparse on head and mesosoma (Crematogaster)