Pseudomyrmex veneficus (Wheeler, 1942)
Worker diagnosis. Relatively small, HW 0.85-0.95; head broad (CI 0.88-0.95); median clypeal lobe laterally rounded; frontal carinae relatively well separated (FCI > 0.04); petiole short and relatively narrow; head densely punctulate, subopaque to sublucid; body pubescence thick and conspicuous, suberect on dorsal surfaces of propodeum and petiole; body very dark greyish-brown to black, mesosoma sometimes contrastingly lighter.
Distribution. Western Mexico (Sinaloa to Michoacán).
Biology. P. veneficus is an obligate acacia-ant, associated primarily with Acacia hindsii. Janzen (1973) gives a detailed description of the ecology and behavior of this highly polygynous species, which forms large, effectively unicolonial populations.