Pictorial key to the ant genera of Illinois

by N.C. Wilkins and S.B. Menke

Fig. 1 Stigmatomma pallipes (antweb.org)

Fig. 2 Tapinoma sessile (antweb.org)

Fig. 3 Tetramorium caespitum (antweb.org)

Fig. 4 Crematogaster cerasi (antweb.org)

A Postpetiole absent; waist consisting of a petiole (abdominal segment 2).


B In some cases, petiole greatly reduced and node vestigial or absent.


C In profile, abdominal segment 3 not markedly smaller in size than segment 4.


D Abdominal segment 3 either confluent with or separated from segment 4 by a slight or moderate constriction.
AA Postpetiole present; waist consisting of two segments. Following the petiole is the postpetiole (abdominal segment 3), which is much smaller than abdominal segment 4 and separated from it by a strong constriction.