Chironomus striatipennis immatures

Fourth instar Larva: a small plumosus-type (length 7-12.3 mm)(fem. 10.9 (9.7-12.3 mm); specimens of Chaudhuri et al (1992) (7.0-8.2 mm) but this may be due to being reared in a laboratory.  Anterior and posterior Ventral tubules about equal length or anterior longer (ant 1.20-1.56 mm, post 1.24-1.48 mm); Lateral projections about 300 (280-320) µm.  Anal tubules about 303 (250-380) µm long and 2.7 times longer than wide.  Salivary reservoir about 53-55.5 µm wide and about 3 times wider than deep.
Gula from pale to (mostly) slightly darkened over posterior 1/3; and frontoclypeus also from pale to occasionally dark, generally the darker specimens are from Uttar Pradesh.
Distance between antennal bases (142.8 (124-163) µm) generally greater than the distance between the S4 setae (137 (127-145) µm).
Mentum (Fig. c) with C2 teeth of central tooth separated and sharp (type IB-III), 4th lateral reduced, sometimes only slightly, or down to level of 4th lateral (type I-ii).  Pecten epipharyngis (Fig. a) with 14.3 (11-17) teeth (type B).
Ventromental plates (Fig. d) separated by 0.27 (0.22-0.32) of the mentum width (ICD), about 38.5 (32-46) striae, VMR about 0.26 (0.22-0.29).
Premandibles with inner tooth about 4.64 (3.6-6) times wider than the outer tooth; outer tooth to fine point, inner to moderate point (Ty.2B).
Antenna (Fig. b) with basal segment relatively long, 2.7-3.7 times longer than wide; Ring organ from about 0.3-0.45 up from base of segment; AR about 1.91 (1.6-2.1); proportions (µm) 93 : 23 : 9 : 11 : 6.
Mandible (Fig. e) with third inner tooth partially or completely separated, and partially pigmented (i.e. type IIB or IIIB, but may be IA or IIA in Jammu & Kashmir), with 15.7 (13-18) furrows near base; 12 (11-14) taeniae in Pecten mandibularis; Mdt-Mat abt 28 µm; MTR about 0.35 (0.30-0.37.

Pupa:  Length about 6.5 (5.4-7.6) mm (male) 5.3 (4.8-5.8) (female), posterior margin of wing case about 1.09-1.28 mm.  The size of the Chaudhuri et al (1992) specimens is lower.  Dark brown, exuvia pale brown.
Head:  Cephalic tubercles about 62 (40-80) µm long and about 48 (40-65) µm wide at the base, with a subterminal seta about 57 µm long.
Thorax:  Prealar tubercle present, not simple, but small, about 25 µm long and 6 µm wide.  Basal ring of respiratory horn with edge thicker at the anterior end, and pinched at the centre, about 129.5 (126-133) µm long and 62 (60-64) µm wide; HR about 2.17.
Abdomen:  About 67 (62-72) recurved hooks on posterior margin of segment II, the hook row covering about 54% of the width of the segment.  Pedes spurii B on segment II, and pedes spurii A on segment IV, while those of segment V and VI are small and mainly identifiable by the spinules, on seg V these spines run all along the edges of the segment.
Caudolateral spur of segment VIII generally with 1 main spine (see below), but occasionally with 1 or 2 subsidiary ones or a broad shoulder.
Anal lobe with about 53 taeniae on each side, mostly in a single row.

Cytology:  Four polytene chromosomes with the pseudothummi-cytocomplex combination AE, BF, CD, G.  Centromeres with some degree of heterochromatinization.
Nucleolus subterminal on arm G.  No nucleoli on long arms.  End of arm G bearing nucleolus, typically unpaired, with BR near other end.
Polymorphism in arms A, B, C, D, E, and F.  Saxena also recorded a tandem fusion between arm A and B, and a small deletion near the distal end of arm B.  The polytene chromosomes are illustrated by Sarkar et al. (2018) but it is not clear whether the heterozygous inversions shown are natural or the result of experimental treatments, given the large number of inversions found in other studies.
stpA1:    1 - 2c, 11 - 7, 4 - 6, 2d - 3, 12 - 19
stpA2: 1a-d, 10d - 12, 3 - 6a, 7 - 9, 4 - 6, 2i - 1e, 10a-c, 16 - 17, 13 - 15, 16 - 19
stpB1:    Puff virtually terminal with only the dark bands (6a-f, 7ab) distal
stpB2:    simple inversion of B1, shares proximal breakpoint with B4, B5, B6.
stpB3:    Slightly longer inversion than B2, distal break at least 10 bands distal of B2 break.
stpB4:    Shares distal break with B2, proximal breakpoint shared with B5, B6 & B8.
stpB5:    Proximal breakpoint shared with B4, B6 & B8, distal with B3.
stpB6:    Proximal breakpoint shared with B4, B5 & B8, distal breakpoint shared with B7.
stpB7:    Proximal breakpoint closer to centromre, distal breakpoint shared with B6.
stpB8:    Proximal breakpoint shared with B4, B5 & B6, distal breakpoint just proximal to puff of group 7.
stpC1:    Characteristic groups 3-4 about 1/3 from centromere.
stpC2:    Simple inversion of almost the whole arm.    Shares proximal breakpoint with C3.
stpC3:    Shares proximal breakpoint with C2 and distal breakpoint with C4.
stpC4:    Shares distal breakpoint with C3 and proximal breakpoint with C5.   (India, Japan & Brazil).
stpC5:    Shares proximal breakpoint with C4.
stpD1:
stpD2:    Small simple proximal inversion.
stpD3:    Simple inversion of distal 2/3 of arm.  Shares distal breakpoint with D4.
stpD4:    Large inversion of about 3/4 of the arm.    Shares distal breakpoint with D3
stpE1:    1a - 13g            i.e. Standard
stpE2:    1 - 2c, 8 - 2d, 9 - 13
stpF1:    1 - 2a, 15e - 11f, 2b - 15f-a, 11a-e, 16 - 23
stpF2:    1a, 21c - 16, 11e-a, 15a - 2b, 11f - 15e, 2a - 1b, 21d - 23     from stpF1 (from Saxena)
stpF3:    1 - 2a, 15e - 14, 18 - 16, 11e-a, 15a - 2b, 11f - 13, 19 - 23     from stpF1 (from Saxena)
stpF4:    1 - 2a, 15e - 14, 16f-a, 11f-a, 15a - 2b, 11f - 13, 16g - 23     from stpF1 (from Saxena)
stpG1:    Nucleolus subterminal.  A large BR may be developed in some localities.

Polytene chromosomes of C. striatipennis