Keyl, 1960
Body
Living larvae are red. Four ventral tubules on the 11th abdominal segment, normally coiled and no tubules on the 10th segment. Procercus and anal tubules present (Wiederholm, 1983; Vallenduuk and Moller Pillot, 2002).
Head
The frontal apotome and gula are pale (Vallenduuk and Moller Pillot, 2002)
Antenna
The antenna consists of 5 segments, the first segment 107 - 144 µm long (Vallenduuk and Moller Pillot, 2002). The blade is not longer than the flagellum. Lauterborn organs distally on the second segment.
Mentum
The mentum has three median teeth and 6 pairs of lateral teeth with mentum type1 Mentum type 1 pict of 2 Mentum type 2 pict. The ventromental plates are wider than the mentum
Labrum
SI is plumose and labral lamellae are normal.
Mandible
The mandible with a pale dorsal tooth, apical tooth dark and 3 inner teeth of type 1 Chiron mand l or 2 Chiron mand ll. The pecten mandibularis is present and seta interna with 4 toothed and plumose branches.
Differential characteristics
Chironomus is the only genus with 2 pairs of tubules on the 11th segment Chir 4 ventral tubules. Some species lack the ventral tubules (C. salinarius Chir no tubules, C, nudiventris and C. agilis). C. salinarius occurs only in brackish and salt water. The latter two species have a pair of lateral setae on segment 10 Chir 2 lateral tubules. These two species can be separated from Einfeldia pagana by the absence of a pit on the frontal apotome.
C. acidophilus can be separated from all other Chironomus by:
Two pairs of ventral tubules on the 11 segment and no tubules on the 10th abdominal segment.
The pale gula, mandible type 1 or 2 and the length of the first antennal segment 107 µm.