Chironomus culterus Das, Majumdar and Hazra 2016

Pupa:  Total length 6.48-7.72 mm.  Yellowish brown, exuviae grey.
Frontal apotome rugulose with subequal frontal setae,  Cephalic tubercles funnel shaped 84-87 µm long and 50-52 µm wide at base.  Antennal sheath 583-587 µm long (not clarified as to whether this is for male pupae).  2 pairs precorneals.  Wing sheath 1.51-1.77 mm in length.
Abdomen yellowish brown, tergite II-VI with median shagreen, VII with subbasal and subcaudal transverse band of shagreen, VIII with 2 patches of median shagreen; segment II with caudolateral PSB (55-59 x 56-62); IV with a caudolateral PSA (62-69 x 50-59).
Hook row separated (unusual and not apparent in figure) with 56-60 hooklets.
Caudolateral spur with a single spine, but may have a small basal one (Fig. 5H).  134-142 taeniae in anal fringe.

Larva:  Head.  Antenna (Figure 5I) 5 segmented, length ratio of flagellomeres I-V: 94.6-98.9 : 12.9-17.2: 8.6-10.17: 4.3-6.45: 4.3-6.45, basal segment larger than flagellum, AR 2.73-2.86; blade 34-46 long and nearly equal to flagellum; accessory blade 16-28 long, ring organ (Figure 5I) 3.5-4.5 in diameter at the basal one-fifth of flagellomere I; length of lauterborn organ nearly equal to length of basal antennal segment, ratio of lauterborn organ and antennal segments 0.72-0.84.
Labrum: S I 20-32 long with finely serrated outer margin, S II 52-64 long with pointed tip, S III and S IV indistinct, S IVA and S IVB prominent 10-11 and 6-7 long respectively, labral lamellae 135-149 long with depressed median part; pecten epipharyngis (Figure 5J) with single row of 14-16 teeth, pecten hypopharyngis pentadactylus, dark and paired structure on each side of mentum.
Premandible (Figure 5K) 57-71 long dark with 5 teeth, pecten premandibularis robust.
Mandible (Figure 5L) 178-191 long and 63-76 wide with 1 pale dorsal, 1 dark apical and 3 dark inner teeth, seta subdentalis 37-51 long, seta interna plumose with 3 basal stalks, pecten mandibularis filiform, sensilla minusculum 2. Maxillary palpus well developed with lacinial chaeta.
Mentum (Figure 5M) 142-157 wide with crenate median and 6 pairs of gradually decreasing lateral teeth, two smaller outer teeth fused at the base of central one; ventromental plate 58-72 wide, margin serrated and separated by a distance of 118-134 greater than median mentum tooth.
Body.  Anterior and posterior parapods with sharp, curved and pointed apex claws (Figure 5N).  Anal tubules 0.96-1.44 long, ventral tubules slender (does this mean they are and 1.84-2.44 long; procercus with 6-8 anal setae in each.

Found: Type locality - Kalimpong (27.04°N, 88.28°E 1247 m a.s.l.), West Bengal.

Another species in which the larva has a five-toothed premandible; perhaps some relationship to C. clavipenis.