C. vitellinus Freeman 1961

Male:
Wing length 2.64 (2.07-3.00) mm, width 0.64 (0.56-0.73) mm; VR 1.05 (1.02-1.08); 2 Scf on brachiolum, 19.5 (17-22) setae on squamal fringe.
Freeman (1961) quotes the AR as about 4.5, but in other populations the AR is lower: 3.34 (2.89-4.5).
Head: Frontal tubercles 43.7 (30-55) µm long and 2.4-2.6 times longer than wide.
Palpal proportions (micron): 49 : 46 : 157.5 : 191 : 272 :P5/P4 1.45 (1.25-1.74); P5/P3 1.79 (1.40-2.17).  Clypeus about 0.60 (0.47-0.75) of antennal pedicel, with about 18.2 (11-23) setae.
Thoracic setae: acrostichal at least 11-14; dorsocentrals 9.7 (5-14); Prealar 4.25 (3-5); Supraalar 1; Scutellar 10.75 (13-17), 2-6 in anterior row, 5-11 in posterior row.
Leg lengths (microns) and proportions as follows:

	Fe	Ti	Ta1	Ta2	Ta3	Ta4	Ta5	LR	F/T	BR
PI	1245	970	1480	895	715	740	340	1.56-1.93	1.11-1.27	0.46-1.60
PII	1215	1085	715	370	270	180	135	0.64-0.70	1.10-1.17	-
PIII	1325	1345	1075	575	425	270	165	0.77-0.83	0.95-1.00

Tergite IX with 6.3 (5-9) setae in individual pale patches.
Hypopygium with narrow anal point expanded at distal end, strongly turned down and narrow in lateral aspect (see above); Superior Volsella well developed and curved, perhaps closest to E(g) of Strenzke (1959); IVo reaching about to 1/3-1/2 length of gonostylus, with 12-14 incurved simple setae (although Tokunaga's figure appears to show them as forked).  Gonostylus may not be as swollen as shown in Tokunaga's figure but narrows conspicuously over posterior third to half, with 5+1 setae at the tip.

Male terminalia from Tokunaga 1964

Female

Go to Freeman's (1961) description and that of a paratype female

Other specimens (including those of Tokunaga 1964):Wing length 2.70 (2.07-2.93) mm, width 0.81 (0.66-0.96) mm; VR 1.09 (1.07-1.11); 2–3 Scf on brachiolum; 15 (14-16) setae in squamal fringe.
Coloration essentially as in male.
Head: Frontal tubercles present but may be small (6 µm long and equally wide).
Antennal segments (micron) with percentage neck in brackets: 265 (27) : 126 (46) : 130 (49) : 129 (49) : 240; AR 0.37 (0.34-0.43); A5/A1 1.26 (1.07-1.45).
Palpal segments (micron): 55 : 54 : 206 : 220 : 366; P5/P4 1.6-1.7; P5/P3 1.8.
Clypeus heart-shaped, about 1.32-1.45 wider than antennal pedicel; abt 25 (20-31) setae.
Thoracic setae: Acrostichals – abt 10-12; Humerals – 3.6 (3-5), mostly linear but may be grouped (e.g. as a triangle); Dorsocentrals – 17.8 (11-25); 21.5 (16-28) including the Humerals; Prealars – 5.5 (4-7); Scutellars in two rows – 2.3 (0-6) in anterior row and 10 (6-12) in posterior row (total abt 6-18).
Leg lengths (microns) and proportions as follows:

	Fe	Ti	Ta1	Ta2	Ta3	Ta4	Ta5	LR	F/T	BR
PI	1475	925	1635	1025	875	885	355	1.69-1.84	1.55-1.63	0.94-0.97
PII	1270	1155	660	320	240	180	127.5	0.55-0.58	1.08	-
PIII	1350	1470	925	455	400	265	160	0.58-0.63	0.92-1.08

Anterior Ta4 longer than Ta3.

Sasa & Hasagawa (1983) imply that the last couple of segments may be darkenend.  Segment X usually a half-oval (2.6-2.7 times longer than greatest width) with about 10-13 setae.  Sasa & Hasagawa (1983) note that the cercus is roughly rhombic, 112x152 µm; usually with a ventral basal bulge.

Pupa:  has been described by Chaudhuri et al. (1992), and the abdomen illustrated by P.S. Cranston in his Electronic Guide to Chironomidae of Australia, as C. vitellinus (below).  This illustration is reproduced (with permission).
Length: Male 6.40 (6.38-6.70) mm; female 7.01 (6.90-7.14) mm (6-7 mm in Lenz 1937).  Exuviae grey.  Frontal tubercles 81-110 µm long and 51-70 µm in diameter, subapical seta 38-90 µm long, i.e. about as long as the tubercles.  It is possible there is slight development of frontal warts (see Cranston figure).  Respiratory base about 110-157 x 53-81 µm wide.  2 pairs of precorneal setae.
Abdomen with Pedes spurii A caudolateral on segments IV-VI, that on segment IV about 140 (116-157) x 91 (71-111) µm wide and about 21 (18-22)% of the segment length; Pedes spurii B basolateral on segment I and caudolateral on segment II, which also bears a caudal row of about 72.3 (66-81) hooks which occupy 61-64% of the segment width.  Caudolateral spur of segment VIII with 1-4 spines, although commonly only 1 is long.  Swim fin with aboout 70-72 taeniae in a single row proximally and a double row distally.

Fourth instar larva: a medium sized, essentially plumosus-type larva (fem. 9.3-13.7 mm (11), male 13.0 mm (1)), although lateral tubules (about 380 micron long) are more ventrally placed than in other species.  Chaudhuri et al. (1992) show the VT arising very close together, but this is not normal in this species from other countries.  Anal tubules about 425 microns long, with median constriction.
Gula pale or slightly darkened on posterior third;  frontoclypeus pale.
Mentum (Fig. c) with the central trifid tooth set below the 1st laterals, and the c2 teeth markedly separated from c1 tooth (type III) and pointed towards it; 4th laterals at most slightly reduced (type I).
Pecten epipharyngis (Fig. a) with about 12-13 often irregular teeth (type D).  Ventromentum (Fig. d) about 3.7 times wider than deep, with about 27-28 striae.
Antenna (Fig. b) with the basal segment about 4 times as long as wide; AR about 2.4; ratio of segments 125 : 29 : 6 : 9 : 5.
Distance between S4 setae slightly larger than with between antennal bases.
Mandible (Fig. e) with third inner tooth darkened and completely separated (type IIIB), with three spines on inner margin, and about 12-13 furrows on the outer surface at the base.

The larva is most readily recognised by the unusual premandible, which has 7 teeth rather than the usual two, as well as the lowered central trifid tooth of the mentum.

Some larval characters have been illustrated by P.S. Cranston in his Electronic Guide to Chironomidae of Australia, as C. vitellinus.  These are reproduced here (with permission).

Cytology:  4 polytene chromosomes chromosomes with the thummi arm combination AB, CD, EF, G, but Keyl arms very difficult to recognize.
Nucleolus virtually terminal in arm G, with large Balbiani Ring near middle of the arm; closely paired.  No nucleolus in long chromosomes.

Found: Type locality Australia - Northern Territory - Darwin
            Townsville (-19.25°S, 148.78°E).
            Fiji - Labasa, Vanua Levu (-16.33°S, 179.50°E) and Nadi, Viti Levu (-17.67°S, 177.50°E).
            Micronesia - Caroline Islands and Marshall Islands.
            Papua New Guinea - Mafulu (1200 m) Paratype, Lae-Goroka Road (-8.50°S, 146.00°E), Eastern Highlands Province;
            Sogeri (-7.56°S, 143.43°E), Central Province.
            Other regions:
            Japan - Shizuoka, Shizuoka Prefecture, Honshu (34.989°N; 138.38°E).
            Malaysia - Minden (5.13°N; 100.13°E) and Bukit Merah Rice Res. Stn, Permatang Pauh, Penang; Tregganu.
            ¿Thailand - Ban Bangkanark, Chachoengsao Province; San Pa Tong Rice Experimental Station, Amphoe San Pa Tong,
            Chiang Mai Province; Ban Mae Kachiang, Amphoe Wiang Pa Pao, Chiang Rai Province (Hashimoto et al. 1981)
            Central Africa - Blantyre, Malawi.

The adult male was described from Thailand by Hashimoto et al. (1981).  The cytological description given here is based on Australian, Papua New Guinea and Japanese specimens.