Subfamily Trefusiinae Gerlach, 1966

Diagnosis

Trefusiidae . Outer labial sensilla always setose and jointed, usually in separate circle from cephalic setae (except in Trefusialaimus). Amphideal fovea circular, oval, unispiral, cryptospiral, spiral, elongated or pocket-shaped. Buccal cavity small to medium size, funnel-shaped, not cuticularized. Spicules short, arcuate or straight; gubernaculum present or absent, without apophyses. Female reproductive system didelphic with reflexed ovaries, except in Trefusialaimus (outstretched). Male reproductive system usually diorchic (monorchic in Trefusialaimus).