The male of the species is unknown. The female is generally pale orange or yellowish brown, with a body about long. Like most members of the family Oonopidae,
T.stenaspis has only six eyes. Adults, but not immature stages, have hardened, darker plates or
scuta on the abdomen. On the upper surface, the dorsal scutum covers most of the abdomen. On the lower surface, the ventral scutum is divided into two halves by the
epigastric furrow, so that sources variously describe it as one or two scuta, making two or three scuta in total. A diagnostic character of the genus
Triaeris is the long
patella; the patella of the first leg of
T.stenaspis is almost as long as the tibia. In adults, the first leg has three pairs of spines on the ventral surface of the patella and five pairs on ventral surface of the tibia. Immatures have fewer spines. The genitalia are complex, occupying most of the ventral scutum. ==Taxonomy==