A new giant species of the subfamily Rhynchoproctinae with strikingly bi-coloured, red-
yellow legs contrasting with a black body is described: Alienostreptus bicoloripes sp. nov. from Vietnam.
The new species is assigned to the genus Alienostreptus Pimvichai, Enghoff & Panha, 2010 hitherto
comprising one species, A. alienus (Attems, 1936), and differing from other rhynchoproctine genera by
having the femoral spine duplicated. Species of this genus share three synapomorphic characters of the
subfamily, viz (1) anterior coxal fold forms deep concavity in posterior view, (2) posterior coxal fold
very low, and (3) posterior coxal fold with mesal flap. A superficially very similar colourful species
from Borneo, also with bi-coloured legs but clearly not belonging to Alienostreptus due to the position
of ventral soft pads on male legs, is documented based on photographs.