Key to Monomorium  species in or possible in MS and AL (from Creighton 1950 and DuBois 1986)

The first two of the three segments forming the antennal club subequal in length; workers varying somewhat in size, slightly dimorphic
...destructor (Jerdon) (subgenus Parholcomyrmex)
  The three segments of the antennal club successively increasing in length; workers varying very little in size, monomorphic
.....2 (Subgenus Momomorium)
2(1)  The head and thorax densely punctate, opaque, or feebly shining; the color is a clear reddish yellow (generally found in buildings and not in the wild)
  Head and thorax mostly or entirely smooth, strongly shining with only scattered piligerous punctures; color not as above
...3
3(2) Dorsum of propodeum and propodeal declivity of equal length
  Propodeal dorsum and declivity of unequal lengths (either face may be longer)
....4
4(3) Head and gaster brown, alitrunk, petiole, postpetiole, and appendages dirty yellow
  Concolorous dark brown to black or with head greenish brown, alitrunk, petiole, postpetiole, and legs reddish-brown (with green overlay or tint), and gaster black (sometimes with greenish or blueish hues)
...5
5(4)    Length of propodeal dorsum less than length of propodeal declivity
  Length of propodeal dorsum greater than length of propodeal declivity
...6
6(5)  The node of the petiole, in profile, about as high as it is long and the anterior peduncle is distinctively shorter than the base of the node; the mesopleurae and the base of the propodeum are mostly smooth and shining; color of worker and queen blackish
  The node of the petiole, in profile, is somewhat higher than it is long and the anterior peduncle is about as long as the base of the node; mesopleurae and base of propodeum with rugulae or delicate striae; worker brownish-black, sometimes with strong greenish reflections; queen bicolored, head, alitrunk, waist, and appendages, orangish red and gaster blackish with strong metallic green reflections