Chironomus striatipennis immatures

Fourth instar Larva: a small plumosus-type (length 7-12.3 mm)(fem. 10.5-12.3 mm).  Anterior and posterior Ventral tubules about equal length or anterior longer (ant 0.96-1.56 mm, post 0.96-1.48 mm); Lateral projections about 200-320 µm. Anal tubules with dorsal pair about 250-280 µm long, posterior pair abt 280-340 µm, and 2.7-4 times longer than wide.  Salivary reservoir about 90 µm wide and 5.5 times wider than deep.
Gula from pale to dark, which may extend over posterior 2/3; and frontoclypeus also from pale to dark.  Distance between antennal bases (137.2 (124-149) µm) generally greater than the distance between the S4 setae (129.2 (121-137) 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 15.8 (14-18) teeth.
Ventromental plates (Fig. d) separated by 0.24-0.32 of the mentum width, about 37.6 (32-46) striae reaching at least halfway to anterior margin; VMR about 0.24-0.29.
Premandibles with inner tooth at least 2-5.1 times wider than the outer tooth; outer tooth to fine point, inner to moderate point (Ty.2B).
Mandible (Fig. e) with third inner tooth partially or completely separated, and partially pigmented (i.e. type IIB or IIIB), with 14.5 (12-17) furrows near base; Mdt-Mat 23-28 µm; MTR about 0.36-0.37.
Antenna (Fig. b) with basal segment relatively long, 2.7-3.7 times longer than wide; Ring organ from about 0.3-0.5 up from base of segment; AR about 1.93 (1.6-2.1); proportions (µm) 95 : 26 : 9 : 11 : 6.5.
Much of the variability in these larval characters comes from the different Indian samples, as well as the relatively broad distribution.

Pupa:  Length about 5.4-6.8 mm (male) 4.8-5.8 (female), posterior margin of wing case about 1.1 mm.
Head: : Cephalic tubercles about 53-80 µm long and about 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 126 µm long and 60 µm wide.  There are about 3 rough short spines immediately anterior to the basal ring, and a large, possibly muscle scar just posterior to it.
Abdomen:  About 62-80 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.
Caudolateral spur of segment VIII generally with 1 main spine (see below), but occasionally with 1 or 2 subsidiary ones.
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.
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 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.  Appears to occur in India, Japan and Brazil.
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, but not in others (e.g. Japan).

Polytene chromosomes of C. striatipennis