Pictorial key to the ant genera of Illinois
Fig. 74 Myrmecina americana (antweb.org)
Fig. 75 Pheidole bicarinata (antweb.org)
A Petiole short and subcylindrical to subquadrate, without anterior peduncle and with dorsal node absent or rudimentary.
B Propodeum with 2 pairs of teeth: a short pair of teeth anterior to a longer pair on the propodeal angle.
C In side view the ventral margin of the head with a sharp longitudinal carina below the eye.
...Myrmecina
23'
AA Petiole with distinct dorsal node.
BB Propodeum unarmed or armed with a single pair of spines or denticles.
CC Carina as described above absent.