Small to medium sized larvae, up to 5 mm long.
Antenna not longer than 1/2 length of mandible; 3-4 antennal segments present; terminal segment usually longer than that preceding. Blade extending beyond flagellum, often greatly. Lauterborn organs indistinct.
Labrum with SI and SII bifid; SIII and SIV simple. Labral chaetae often numerous. Pecten epipharyngis consisting of 3 usually simple, sometimes serrate spines. Premandible with 2-4 teeth and (possibly always) distinct brush.
Mandible with apical tooth shorter than combined width of 3 inner teeth. Seta subdentalis weak or absent. Seta interna absent.
Mentum with single median tooth of variable shape, sometimes with median projection, sometimes with median indentation; 4 pairs (perhaps always?) of lateral teeth present. Ventromental plate distinct but not extending beyond outer tooth of flattened mentum; second plate present in some species; beard absent.
Maxilla with sensillae on galea and palp weakly developed. Galea elongate and without lamellae (always?). Setae maxillaris short and simple.
Body with anterior parapods present, fused bearing claws. Posterior parapods weak or absent. Procercus absent; 1 anal seta present. 2 pairs of anal tubules present, usually longer than posterior parapods.
Larval Pseudosmittia predominantly are semi-terrestrial to terrestrial, although there are at least two aquatic species (P. oxoniana and P. ruttneri) are aquatic, with the latter species living in the splash-zone of lakes.
Pseudosmittia is species-rich and probably worldwide in distribution. A number of species are associated with mangrove muds and sands in the s.w. Pacific.