Species 3c. C. nr. anthracinus

Adult and Pupa: not known.

Fourth instar larva a medium to large (female 12.4-19.5 mm; male 17.4 mm) plumosus-type; ventral tubules relatively long, posterior pair longer (ant 1.68-1.81, post 1.91-2.44 mm), lateral tubules about 320-360 µm.  Anal tubules long, ventral pair with a median constriction, dorsal pair about 500-800 µm, ventral pair 760-785 µm, respectively 2.5-4.5 and 2.7-3.1 times longer than wide.
Gular region dark over 3/4 or more, extending beyond the width of the mentum and lowering towards the edges, frontoclypeus darkened.
Mentum (Fig. c) about 0.65 of VHL, with pointed teeth; c1 tooth broad with short parallel sides, c2 teeth relatively well separated (type IIA) about 0.26 of MW; 4th laterals reduced about halfway to height of 5th laterals (type I-II).
Ventromentum (Fig. d) with inner margin downturned, about 3.4 times wider than deep and 1.07-1.27 times the mentum width; with 45-59 striae; VMR 0.27-0.29.  Pecten epipharyngis (Fig. a) with about 16 somewhat variable teeth, but essentially ty. B.
Premandible with broad inner tooth about 4-5 times the width of the relatively narrow outer tooth.
Antenna (Fig. b) with relatively long basal segment about 3.4-4.4 times longer than wide, RO about 40% up from base, AR about 2.04-2.23; segment proportion about 144 : 35 : 11 : 14.5 : 7.5.
Distance between the antennal bases greater than that between the S5 setae, which occupy 0.73-0.75 of the frontoclypeus width.  S5 setae at least slightly posterior to the nearby RO.
Mandible (Fig. e) with third inner tooth slightly reduced and moderately colored (type IIB); 15-16 furrows on outer surface at base; 15 taeniae in Pecten mandibularis; Mdt-Mat 43, MTR about 0.45 when not worn.

Cytology:  4 short polytene chromosomes with the thummi arm combination AB, CD, EF, G.
Arm G cloudlike with an almost terminal nucleolus and only four or five obvious bands; often paired only at the nucleolus.  No nucleoli in other chromosomes.

Arm A1:    1 - 2c, 10 - 12, 3 - 2d, 9 - 4, 13 - 19                            i.e. as holomelas, tardus, etc.
Arm E1:    1 - 3e, 5 - 10b, 4 - 3f, 10 - 13                                          i.e. as cingulatus, tardus & sp. 3b.
Arm F1:    1 - 10, 17 - 11, 18 - 23                                                  i.e. as in cucini, tardus & tenuistylus.

Found: Wisconsin - Friebauer Lake, Bayfield Co.


Some larval characters given in Hilsenhoff & Narf (1968) as Chironomus n. sp. C.

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Modified: 19 April 2021
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