Probolomyrmex petiolatus Weber ^HNS (figs. 34, 35)

Probolomyrmex petiolatus Weber ^HNS, 1940, Psyche, Comb., Mass. 47, 76, fig. 1, [[worker]] Type locality: Barro Colorado Island, Panama Canal Zone. Holotype: N. A. Weber Collection (examined).

The unique holotype worker of this species is illustrated in figures 34 and 35. It has the following dimensions: HL, 0.51 mm.; HW, 0.36 mm.; SL, 0.29 mm.; CI, 71; SI, 81; WL, 0.65 mm.; PW, 0.27 mm.; dorsal petiole width, 0.14 mm.; petiolar node index, 52; petiole height, 0.27 mm.; petiolar node length, 0.23 mm.; lateral petiolar index, 85. Weber's original description adequately characterises this distinctive species. The worker of P. petiolatus ^HNS differs from that of the sympatric P. angusticeps ^HNS in its smaller size, with relatively broad head, much shorter scapes, and shorter, more compact petiolar node. The unknown worker of P. boliviensis ^HNS is undoubtedly similar to P. angusticeps ^HNS in these features.

Distribution. - Known only from the type locality, Panama: Barro Colorado Island.

Ecology. - The holotype was collected among leaves and humus on the rainforest floor.