Medium sized to large larvae, up to 12 mm long. Red.
Frontal apotome, clypeus and labrum present, with frontal apotome bearing elliptical fenestra, remaining labral area variably fragmented.
Antenna with 5 segments, diminishing in size distally, Lauterborn organs small, opposite on apex of 2nd segment, with short style. Ring organ in proximal 1/3 of segment 1, seta absent. Blade shorter than flagellum, accessory blade subequal to segment 2.
SI plumose along both sides to base; SII simple; SIII simple; SIV short and slender. Seta praemandibularis simple. Labral lamellae normal, pectinate. Pecten epipharyngis simple with numerous teeth of varying lengths. Premandible with 6 pointed teeth.
Mandible with pale dorsal tooth with 1-2 small subapical toothlets, apical tooth strong, with 3 inner teeth. Pecten mandibularis modestly developed, lamellae simple. Seta subdentalis broadly spatulate, distal margin toothed, scarcely extending beyond edge of mandible. Seta interna inserted on dorsal surface, multi-branched.
Mentum with deeply crenulate trifid median tooth and 6 pairs of lateral teeth on each side, 1st and 2nd appressed. broad and tall. Ventromental plates wider than mentum, separated medially by width of mental tooth, with smooth or finely serrate anterior margin. Setae submenti simple.
Lateral tubules absent, 1 pair of ventral tubules present.
Kiefferulus larvae have a large number (5-7) of slender, pointed, premandibular teeth, as do larvae of Axarus, Lipiniella and some genera of the Harnischia complex. Kiefferulus and larvae previously treated as belonging to the now synonymous genus Nilodorum have an anteromedian mark on the frontal apotome,and rather widely separated ventromental plates. The SI of Kiefferulus is considered to be feathered, in contrast to the deeply palmate SI of Nilodorum, but other features of pupa and adult to not support differentiation.
Larvae of Kiefferulus inhabit sediments of small water bodies. The only European species, K. tendipediformis, is regularly found in dystrophic small water bodies.
At least three species are known from the Holarctic, and species considered previously to belong to separate genus Nilodorum are widespread in Afrotropical, Oriental and Australasia. One species is known from the Afrotropical region and three from Australia.