Taxonomy. The genus Strumigenys is assigned to the tribe Dacetini (Bolton 2003). The genus was recently revised by Bolton (2000), and we follow his concept of the genus (but see also Baroni Urbani & De Andrade 2007). Workers of Vietnamese species have the following features.
Worker monomorphic; head in full-face view elongate-cordiform; posterior margin deeply emarginate in middle; frontal carina and antennal scrobe usually distinct, running dorsolaterally above eye; frontal lobe horizontal, covering antennal insertion; clypeus forming a flat shelf which overhangs basal portion of mandible; mandible sublinear to linear (but rarely shortened and basally thickened), straight or curved, terminating in an apical fork of 2 spiniform teeth; one or two small intercalary teeth or denticles usually present between or below spiniform apical teeth; mandible usually with one preapical tooth; labrum with distal lobes reduced to papillae or vestigial, not arising from across entire width of labrum; antenna 6-segmented, with two apical elongate segments together forming a club; eye small, located ventrolaterally; promesonotum usually more or less raised; promesonotal suture absent dorsally; metanotal groove absent; propodeal spine present or absent; posterior slope of propodeum often marginate laterally with lamelliform appendage; propodeal spiracle located high on side of propodeum and close to or at margin of posterior slope of propodeum; fore coxa with a basal rim or carina; petiole pedunculate, with low node; postpetiole with broad elliptical dorsal mound; spongiform appendages well developed ventrally and laterally on both petiole and postpetiole.
The worker of Strumigenys is similar to that of Pyramica (for distinguishing characters see under Pyramica ).
Vietnamese species. Ten species are known from Vietnam: feae Emery [= sp. eg-3; = sp. 44 of SKY: Eguchi et al., 2005] (Ba Vi, Nam Cat Tien, Phu Quoc, Pu Mat, Tay Yen Tu); lewisi Cameron [= sp. eg-6; = sp. 33 of SKY: Yamane et al., 2003] (Ba Vi, Sa Pa, Tam Dao, Van Ban); rallarhina Bolton [= sp. eg-7; = sp. 39, 46 of SKY: Yamane et al., 2005] (Ba Vi, Chua Yen Tu, Cuc Phuong, Phu Quoc, Pu Mat, Tay Yen Tu, Van Ban); sydorata Bolton [= sp. eg-9] (Cuc Phuong, Nam Cat Tien, Phu Quoc, Pu Mat); sp. eg-1 [cf. nanzanensis Lin et Wu] (Cuc Phuong, Phu Quoc, Pu Mat, Tay Yen Tu, Van Ban); sp. eg-2 (Tay Yen Tu); sp. eg-5 [cf. heteropha Bolton] (Tay Ye n T u); sp. eg-8 (Cuc Phuong, Pu Mat); sp. eg-10 (Pu Mat); sp. eg-11 (Nam Cat Tien).
Bionomics. The majority of species of Strumigenys are litter dwellers in well-developed forest. Nests are often found in and under rotting twigs and wood fragments on the forest floor. Because we have not yet employed Winkler bags, used to extract small soil animals from litter, our collection of Strumigenys species may under-represented.