Oriental Chironomus: C. fortibracchius Das, Majumdar and Hazra 2016.

Chironomus fortibracchius Das, Majumdar and Hazra 2016

Adult

Male:
Wing length 2.38-2.86 mm; width 0.52-0.63 mm. AR 3.16-3.18.
Head and antenna dark brown; thorax yellowish brown, wings light yellow; postnotum brown.
Frontal tubercles 52-59 µm long and 30-37 µm wide, i.e. 1.59-1.73 times longer than wide; clypeus 170-181 µm long and 102-112 µm wide, with 24-26 setae. Ratio of papal segments: 51-68 : 34-51 : 170-187 : 136-153 : 153-170; P5/P4 1.11-1.25; P5/P3 0.90-1.0.
Thoracic setae: 8-10 acrostichals; 10-12 dorsocentrals; 4-6 prealars; 14-16 scutellars.
2 Scf on brachiolum, 16-17 setae on squamal fringe; VR 0.90-0.95.
Legs pale yellow and abdomen yellowish brown; tergites II-IV with median dark spots.
Leg lengths (µm) and proportions:

	Fe	Ti	Ta1	Ta2	Ta3	Ta4	Ta5	LR	F/T	BR
PI	1080-1120	920-960	1680-1720	800-840	720-760	680-720	360-400	1.79-1.81	1.19	1.78-1.80
PII	960-1000	1000-1040	640-680	360-380	240-300	240-280	120-160	0.62-0.64	-	3.71-3.74
PIII	1160-1200	1240-1280	1000-1020	560-580	400-440	240-260	160-200	0.53-0.56	-	2.68-2.70

Male hypopygium, wing, fore tibial scale and claw of adult male of C. fortibrachius Das, Majumdar & Hazra, 2016

About 10 setae on TIX apparently in individual spots.
Hypopygium with anal point narrow at base and widened (spoon-like) at tip. Superior volsella closest to S(a)-type of Strenzke (1959); Inferior volsella reaching almost to the end of the anal point and about 1/3 along the gonostylus, which is quite swollen and narrows relatively gently over distal third, with about 4 setae at the end.

Female: Not known.

Pupal characters of C. fortibrachiusDas, Majumdar & Hazra, 2016

Pupa: Total length 6.68-7.92 mm, wing sheath 1.47-1.49 mm long. Yellowish brown, exuviae grey. Cephalic tubercles 73-78 µm long and 71-74 µm wide at base; antennal sheath 714-731 µm long. Thorax rugose. Respiratory base not measured, but illustrated (6E, above) as constricted in the middle and with HR about 2.
Abdomen yellowish brown, shagreen pattern shown in figure 6F: tergite I bare, tergites II-IV with median shagreen, V little dark, VI with one small light median and 2 small patches of dark basomedian shagreen. Hook row of 68-74 hooklets, separated in mid-line. PSB on segment II (65-69 x 52-56 µm), PSA on segment IV (69-74 x 60-65 µm). Caudolateral spur of segment VIII (6H, above) 142-147µm long with a sharp spine. 172-178 taeniae on anal lobe.

Larval characters of C. fortibrachius Das, Majumdar & Hazra, 2016

Fourth instar larva: Total length 6.76-7.04 mm; deep red in colour.  No details of head coloration or larval type given.
Antenna with basal segment about 3.3 times longer than wide, RO about a thrd up from the base of the segment.  Length of segments (micron): 107.5-111.8 ; 34.4-38.7 ; 12.9-17.2 ; 8.6-10.75 ; 4.3-6.45.  AR 1.78-1.80.  RO about a third up from base of segment.
PE with 14-16 teeth, perhaps type A.  Mentum of ty. 2 with center trifid tooth lower than lateral teeth, possibly type IIA.
Premandible with 2 relatively narrow teeth, possibly Ty. 1(?).
Mandible 111-115 µm long, of ty. IIIC; no information on Pecten mandibularis or basal striae, MTR about 0.3.
Ventral tubules 150-160 µm long, anal tubules 116-125 µm long.

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

Shows relationship to C. fortistylus in wing and venation pattern, but it might have some relationship to C. bipunctus which also occurs at high elevations.

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